Methods and materials for assessing response to plasmablast- and plasma cell-depleting therapies

ABSTRACT

The present disclosure relates to anti-CD38 antibodies and their use as therapeutics and diagnostics. The present disclosure further relates to methods of treating autoimmune diseases, such as systemic lupus erythematosus and rheumatoid arthritis. The present disclosure further relates to diagnostic assay methods for identifying patients having autoimmune diseases for treatment.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.16/317,606, filed Jan. 14, 2019, which is a national stage entry under35 USC 371 of PCT International Application Number PCT/US2017/042128,filed Jul. 14, 2017, which claims priority under 35 U.S.C. § 119(e) toU.S. Provisional Application Ser. No. 62/362,963 filed on Jul. 15, 2016,the entire disclosures of which are incorporated herein by reference.

INCORPORATION BY REFERENCE OF MATERIAL SUBMITTED ELECTRONICALLY

The instant application contains a Sequence Listing which has beensubmitted electronically in XML file format and is hereby incorporatedby reference in its entirety. Said XML file, created on Feb. 15, 2023,is named 101588-5014-US01_Sequence_Listing.xml and is 47,146 bytes insize.

FIELD

The present disclosure relates to anti-CD38 antibodies and their use astherapeutics and diagnostics. The present disclosure further relates tomethods of treating autoimmune diseases, such as systemic lupuserythematosus and rheumatoid arthritis. The present disclosure furtherrelates to diagnostic assay methods for identifying patients havingautoimmune diseases for treatment.

BACKGROUND

Plasma cells and plasmablasts are antibody-secreting cells (ASCs) thatare important for pathogenic processes associated with systemic lupuserythematosus (SLE) and rheumatoid arthritis (RA). They have beenimplicated in numerous antibody-driven autoimmune diseases includingmyasthenia gravis, Sjogrens syndrome, multiple sclerosis (MS) andautoimmune thyroditis. See Jacobi A M, Mei H, Hoyer B F, et al., AnnRheum Dis (2010) 69(1):305-8; Dorner T, Isenberg D, Jayne D, et al.,International Roundtable on B cells as Therapeutic Target forIntervention, Autoimmun Rev (2009) 9(2):82-9; Tipton C M, Fucile C F,Darce J, et al., Nat Immunol (2015) 16(7):755-65; and Cepok S, Rosche B,Grummel V, et al., Brain (2005) 128(Pt 7):1667-76. Plasmablasts areterminally differentiating B cells that are rapidly produced with themajority becoming short-lived effector cells and the minority becominglong-lived plasma cells.

Most B cells express CD20 and are effectively and durably depleted byantibody therapeutics directed against this cell surface protein. SeeSilverman G J, Arthritis Rheum (2006) 54(8):2356-67. However, some Blineage cells, such as plasmablasts and plasma cells, do not expressappreciable amounts of CD20 and are not effectively reduced by directCD20 depletion. See Silverman 2006. Therefore the ability ofCD20-directed drugs to impact this cell population is limited todepleting the CD20+ B cell population that may eventually differentiateinto plasmablasts with little effect on already formed plasmablasts andplasma cells. See Silverman G J and Boyle D L, Immunol Rev (2008)223:175-85.

Clinical studies involving SLE patients have shown that high levels ofplasmablasts prior to anti-CD20 treatment correlate with inefficient Bcell depletion in the blood. In addition, incomplete depletion ofplasmablasts in the blood may have clinical consequences, includingfaster relapse and reduced survival. See Vital E M, Rawstron A C, DassS, et al., Arthritis Rheum (2011) 63(3):603-8. Similar findings havebeen demonstrated for RA patients treated with anti-CD20 monclonalantibodies. See Dass S, Rawstron A C, Vital E M, et al., Arthritis Rheum(2008) 58(10):2993-9; and Owczarczyk K, Lal P, Abbas A R, et al., SciTransl Med (2011) 3(101):101ra92.

To address these issues, methods have been developed to indirectlymonitor plasmblast and plasma cell levels in the blood by evaluatingmRNA transcripts expressed primarily in these cell types. See Vital E M,Dass S, Buch M H, et al., Arthritis Rheum (2011) 63(10):3038-47;Streicher K, Morehouse C A, Groves C J, et al., Arthritis Rheumatol(2014) 66(1):173-84; and Owczarczyk, 2011. Using this method, CD20non-responders were retrospectively identified as those patients withhigh levels of IgJ (immunoglobulin J chain) enriched in plasmablasts andplasma cells and low levels of FCRL5 (Fc receptor-like 5 protein) whichis expressed in CD20+ non-plasmablasts.

This indirect approach is simple and can be utilized in most clinicalsituations. Blood samples are collected using commonly available sampletubes (e.g. Paxgene tubes) and when stored appropriately have longstability. However, transcript analyses in whole blood does not easilypermit direct quantification of the number of plasmablast and plasmacells, and depending on the exclusivity of transcripts evaluated in thiscell population, changes in other cell types could influence theresults.

Direct measurement of plasmablast and plasma cell levels before or inresponse to therapies that affect B cells should help avoid this issue.However, plasmablast viability quickly declines after venipuncture.Using current methodologies, monitoring plasmablast levels requiressame-day processing, which is challenging to standardize among differentclinical sites.

Although plasmablasts and plasma cells do not express appreciableamounts of CD20, these cells, along with NK cells, constitutivelyexpress high levels of CD38, as do B cells and T cells, which upregulate CD38 expression upon activation. See Malavasi F, Deaglio S,Funaro A, et al., Physiol Rev (2008) 88(3):841-86. CD38, also known ascyclic ADP ribose hydrolase, is a type II transmembrane glycoproteinwith a long C-terminal extracellular domain and a short N-terminalcytoplasmic domain. CD38 is a member of a group of related membranebound or soluble enzymes, comprising CD157 and Aplysia ADPR cyclase.This family of enzymes has the unique capacity to convert NAD to cyclicADP ribose or nictotinic acid-adenine dinucleotide phosphate.

Recent studies in humans indicate anti-CD38 mAbs can deplete multipleblood cell types, including plasmablasts and plasma cells.

BRIEF SUMMARY OF THE INVENTION

Anti-CD38 antibodies, when combined with measurement of plasmablastsand/or plasma cells before or during treatment, may be used to treatpatients suffering from rheumatoid arthritis, systemic lupuserythematosus or other autoimmune disease, who are unable to reachdisease remission with CD20-based therapies or other therapies that donot durably deplete plasmablasts and/or plasma cells.

One aspect of the invention provides a method of treating a disease in apatient, the method comprising administering a therapeutically effectiveamount of an anti-CD38 antibody to the patient, wherein the anti-CD38antibody is an isolated antibody which specifically binds human CD38(SEQ ID NO: 1), the disease is an autoimmune disease, and the patientwas shown to have, prior to treatment with the anti-CD38 antibody, anelevated level of CD38-expressing cells relative to a control subject.

Another aspect of the invention provides a method of treating a diseasein a patient, the method comprising administering a therapeuticallyeffective amount of an anti-CD38 antibody to the patient, wherein theanti-CD38 antibody is an isolated antibody which specifically bindshuman CD38 (SEQ ID NO:1), the disease is an autoimmune disease, and thepatient was shown to have, following treatment with an anti-CD20antibody, an elevated level of CD38-expressing cells relative to acontrol subject.

An additional aspect of the invention provides a method of treating adisease in a patient, the method comprising administering atherapeutically effective amount of an anti-CD38 antibody to thepatient, wherein the anti-CD38 antibody is an isolated antibody whichspecifically binds human CD38 (SEQ ID NO:1), the disease is anautoimmune disease, and a biological sample obtained from the patientprior to treatment with the anti-CD38 antibody was shown to have anelevated level of CD38-expressing cells relative to a control subject.

A further aspect of the invention provides a method of treating adisease in a patient, the method comprising administering atherapeutically effective amount of an anti-CD38 antibody to thepatient, wherein the anti-CD38 antibody is an isolated antibody whichspecifically binds human CD38 (SEQ ID NO:1), the disease is anautoimmune disease, and a biological sample obtained from the patientfollowing treatment with an anti-CD20 antibody was shown to have anelevated level of CD38-expressing cells relative to a control subject.

Another aspect of the invention provides a method of treating a diseasein a patient, the method comprising administering a therapeuticallyeffective amount of an anti-CD38 antibody to the patient, wherein theanti-CD38 antibody is an isolated antibody which specifically bindshuman CD38 (SEQ ID NO:1), the disease is an autoimmune disease, and abiological sample obtained from the patient prior to treatment with theanti-CD38 antibody was shown to have an elevated level of plasma cellsand plasmablasts relative to a control subject by assaying for free Iglight chains.

An additional aspect of the invention provides a method of treating adisease in a patient, the method comprising administering atherapeutically effective amount of an anti-CD38 antibody to thepatient, wherein the anti-CD38 antibody is an isolated antibody whichspecifically binds human CD38 (SEQ ID NO:1), the disease is anautoimmune disease, and a biological sample obtained from the patientfollowing treatment with an anti-CD20 antibody was shown to have anelevated level of plasma cells and plasmablasts relative to a controlsubject by assaying for free Ig light chains.

Still another aspect of the invention provides a method of treating adisease in a patient, the method comprising administering atherapeutically effective amount of an anti-CD38 antibody to thepatient, wherein the anti-CD38 antibody is an isolated antibody whichspecifically binds human CD38 (SEQ ID NO:1), the disease is anautoimmune disease, and a biological sample obtained from the patientprior to treatment with the anti-CD38 antibody was shown to have anelevated level of in a CD38-expressing cell of a specific mRNA or groupof mRNAs relative to a control subject.

A further aspect of the invention provides a method of treating adisease in a patient, the method comprising administering atherapeutically effective amount of an anti-CD38 antibody to thepatient, wherein the anti-CD38 antibody is an isolated antibody whichspecifically binds human CD38 (SEQ ID NO:1), the disease is anautoimmune disease, and a biological sample obtained from the patientfollowing treatment with an anti-CD20 antibody was shown to have anelevated level of total CD38-expressing cell mRNA relative to a controlsubject.

An additional aspect of the invention provides a method of treating adisease in a patient, the method comprising administering atherapeutically effective amount of a first anti-CD38 antibody to thepatient, wherein the first anti-CD38 antibody is an isolated antibodywhich specifically binds human CD38 (SEQ ID NO:1), the disease is anautoimmune disease, and a biological sample obtained from the patientprior to treatment with the anti-CD38 antibody was shown to have anelevated level of CD38-expressing cells relative to a control subject byflow cytometry.

Another aspect of the invention provides a method of treating a diseasein a patient, the method comprising administering a therapeuticallyeffective amount of a first anti-CD38 antibody to the patient, whereinthe first anti-CD38 antibody is an isolated antibody which specificallybinds human CD38 (SEQ ID NO:1), the disease is an autoimmune disease,and a biological sample obtained from the patient following treatmentwith an anti-CD20 antibody was shown to have an elevated level ofCD38-expressing cells relative to a control subject by flow cytometry.

A further aspect of the invention provides a method for assayingCD38-expressing cells in whole blood, the method comprising:

-   -   a) obtaining a sample of whole blood from a subject, wherein the        sample includes red blood cells, white blood cells, and an        anticoagulant;    -   b) lysing the red blood cells to form a treated sample;    -   c) freezing the treated sample to a temperature of about −20° C.        or less within about 24 hours of obtaining the sample to form a        frozen sample;    -   d) measuring the amount of CD38-expressing cells in the sample        within about 72 hours of obtaining the sample, wherein the        frozen sample is warmed to room temperature before measuring the        amount of CD38-expressing cells.

Provided herein are reagents and methods for binding to CD38 andmethods, for treating CD38 associated diseases and detecting CD38 usingCD38-specific binding agents including anti-CD38 antibodies.

Accordingly, in some embodiments, an isolated antibody specific forhuman CD38 (SEQ ID NO:1) and cynomolgus CD38 (SEQ ID NO:2) is describedfor use in connection with the various aspects of the invention. In someembodiments, the isolated antibodies described herein can be composed ofa heavy chain variable region and a light chain variable region, whereinthe heavy chain variable region comprises three complementarydetermining regions (CDRs), described herein as HCDR1, HCDR2, and HCDR3,and wherein the light chain variable region comprises three CDRs,described herein as LCDR1, LCDR2, and LCDR3. The sequences of the CDRsare represented by: HCDR1 (SEQ ID NO:3), HCDR2 (SEQ ID NO:4), HCDR3 (SEQID NO:5), LCDR1 (SEQ ID NO:6), LCDR2 (SEQ ID NO:7) and LCDR3 (SEQ IDNO:8).

In other embodiments, the isolated antibody can comprise a heavy chainvariable region, wherein the sequence of heavy chain variable regioncomprises SEQ ID NO:9. In other embodiments, the isolated antibody cancomprise a light chain variable region, wherein the sequence of thelight chain variable region comprises SEQ ID NO:10. In otherembodiments, the heavy chain variable region comprises SEQ ID NO:9 andthe light chain variable region comprises SEQ ID NO: 10.

In some embodiments, the isolated antibody can comprise a heavy chainvariable region, wherein the sequence of heavy chain variable regioncomprises SEQ ID NO:9. In other embodiments, the isolated antibody cancomprise a light chain variable region, wherein the sequence of thelight chain variable region comprises SEQ ID NO:10. In otherembodiments, the heavy chain variable region comprises SEQ ID NO:9 andthe light chain variable region comprises SEQ ID NO:10. This combinationof heavy chain variable region and light chain variable region isreferred to as Ab79. In some embodiments, the isolated antibody includesan Fc domain. In other embodiments, the Fc domain is a human Fc domain.In still other embodiments, the Fc domain is a variant Fc domain.

In some embodiments, an isolated antibody specific for human CD38 (SEQID NO:1) and cynomolgus CD38 (SEQ ID NO:2) is described for use inconnection with the various aspects of the invention. In someembodiments, the isolated antibodies described herein can be composed ofsix CDRs, wherein each CDR of this antibody can differ from SEQ ID NO:3,SEQ ID NO:4, SEQ ID NO:5, SEQ ID NO:6, SEQ ID NO:7, and SEQ ID NO:8 by0, 1, or 2 amino acid substitutions.

In other embodiments, an isolated antibody specific for human CD38 (SEQID NO:1) and cynomolgus CD38 (SEQ ID NO:2) is described for use inconnection with the various aspects of the invention. The isolatedantibodies described herein can be composed of a heavy chain variableregion and a light chain variable region, wherein the heavy chainvariable region comprises three complementary determining regions(CDRs), described herein as HCDR1, HCDR2, and HCDR3, and wherein thelight chain variable region comprises three CDRs, described herein asLCDR1, LCDR2, and LCDR3. The sequences of the CDRs are represented by:HCDR1 (SEQ ID NO:13), HCDR2 (SEQ ID NO:14), HCDR3 (SEQ ID NO:15), LCDR1(SEQ ID NO:16), LCDR2 (SEQ ID NO:17) and LCDR3 (SEQ ID NO:18).

In some embodiments, the isolated antibody can comprise a heavy chainvariable region, wherein the sequence of heavy chain variable regioncomprises SEQ ID NO: 19. In other embodiments, the isolated antibody cancomprise a light chain variable region, wherein the sequence of thelight chain variable region comprises SEQ ID NO:20. In some embodiments,the isolated antibody can comprise a heavy chain and a light chain,wherein the heavy chain sequence comprises SEQ ID NO:19 and the lightchain comprises SEQ ID NO:20.

In other embodiments, the isolated antibody can comprise a heavy chainvariable region, wherein the sequence of heavy chain variable regioncomprises SEQ ID NO:19. In other embodiments, the isolated antibody cancomprise a light chain variable region, wherein the sequence of thelight chain variable region comprises SEQ ID NO:20. In otherembodiments, the heavy chain variable region comprises SEQ ID NO:19 andthe light chain variable region comprises SEQ ID NO:20. This combinationof heavy chain variable region and light chain variable region isreferred to as Ab19.

In other embodiments, an isolated antibody specific for human CD38 (SEQID NO:1) and cynomolgus CD38 (SEQ ID NO:2) is described for use inconnection with the various aspects of the invention. The isolatedantibodies described herein can be composed of six CDRs, wherein eachCDR of this antibody can differ from SEQ ID NO:13, SEQ ID NO:14, SEQ IDNO:15, SEQ ID NO:16, SEQ ID NO:17, and SEQ ID NO:18 by 0, 1, or 2 aminoacid substitutions.

In some embodiments, an isolated anti-CD38 antibody is provided thatbinds specifically to human CD38 (SEQ ID NO:1) and cynomolgus CD38 (SEQID NO:2), wherein the antibody binds to human CD38 with a KD of about10⁻⁶, 10⁻⁷, 10⁻⁸, 10⁻⁹ or more and binds cynomolgus CD38 with a KD ofabout 10⁻⁶, 10⁻⁷, 10⁻⁸, 10⁻⁹ or more.

In some embodiments, antibodies that compete with Ab79 and/or Ab19 forbinding to human CD38 and/or cynomolgus CD38 are provided.

The methods of the present disclosure can be described as embodiments inany of the following enumerated clauses. It will be understood that anyof the embodiments described herein can be used in connection with anyother embodiment(s) described herein to the extent that the combinedembodiments do not contradict one another.

1. A method of treating a disease in a patient, the method comprisingadministering a therapeutically effective amount of an anti-CD38antibody to the patient, wherein the anti-CD38 antibody is an isolatedantibody which specifically binds human CD38 (SEQ ID NO:1), the diseaseis an autoimmune disease, and the patient was shown to have, prior totreatment with the anti-CD38 antibody, an elevated level ofCD38-expressing cells relative to a control subject.

2. A method of treating a disease in a patient, the method comprisingadministering a therapeutically effective amount of an anti-CD38antibody to the patient, wherein the anti-CD38 antibody is an isolatedantibody which specifically binds human CD38 (SEQ ID NO:1), the diseaseis an autoimmune disease, and the patient was shown to have, followingtreatment with an anti-CD20 antibody, an elevated level ofCD38-expressing cells relative to a control subject.

3. A method of treating a disease in a patient, the method comprisingadministering a therapeutically effective amount of an anti-CD38antibody to the patient, wherein the anti-CD38 antibody is an isolatedantibody which specifically binds human CD38 (SEQ ID NO:1), the diseaseis an autoimmune disease, and a biological sample obtained from thepatient prior to treatment with the anti-CD38 antibody was shown to havean elevated level of CD38-expressing cells relative to a controlsubject.

4. A method of treating a disease in a patient, the method comprisingadministering a therapeutically effective amount of an anti-CD38antibody to the patient, wherein the anti-CD38 antibody is an isolatedantibody which specifically binds human CD38 (SEQ ID NO:1), the diseaseis an autoimmune disease, and a biological sample obtained from thepatient following treatment with an anti-CD20 antibody was shown to havean elevated level of CD38-expressing cells relative to a controlsubject.

5. A method of treating a disease in a patient, the method comprisingadministering a therapeutically effective amount of an anti-CD38antibody to the patient, wherein the anti-CD38 antibody is an isolatedantibody which specifically binds human CD38 (SEQ ID NO:1), the diseaseis an autoimmune disease, and a biological sample obtained from thepatient prior to treatment with the anti-CD38 antibody was shown to havean elevated level of CD38-expressing plasmabalst and plasma cellsrelative to a control subject by assaying for free Ig light chains.

6. A method of treating a disease in a patient, the method comprisingadministering a therapeutically effective amount of an anti-CD38antibody to the patient, wherein the anti-CD38 antibody is an isolatedantibody which specifically binds human CD38 (SEQ ID NO:1), the diseaseis an autoimmune disease, and a biological sample obtained from thepatient following treatment with an anti-CD20 antibody was shown to havean elevated level of CD38-expressing cells relative to a control subjectby assaying for free Ig light chains.

7. A method of treating a disease in a patient, the method comprisingadministering a therapeutically effective amount of an anti-CD38antibody to the patient, wherein the anti-CD38 antibody is an isolatedantibody which specifically binds human CD38 (SEQ ID NO:1), the diseaseis an autoimmune disease, and a biological sample obtained from thepatient prior to treatment with the anti-CD38 antibody was shown to havean elevated level of at least one gene enriched in a CD38-expressingcell relative to a control subject.

8. A method of treating a disease in a patient, the method comprisingadministering a therapeutically effective amount of an anti-CD38antibody to the patient, wherein the anti-CD38 antibody is an isolatedantibody which specifically binds human CD38 (SEQ ID NO:1), the diseaseis an autoimmune disease, and a biological sample obtained from thepatient following treatment with an anti-CD20 antibody was shown to havean elevated level of at least one gene enriched in a CD38-expressingcell relative to a control subject.

9. The method according to any one of the preceding clauses, wherein theanti-CD38 antibody comprises:

-   -   a) a heavy chain variable region comprising:        -   i) a first CDR comprising SEQ ID NO: 3;        -   ii) a second CDR comprising SEQ ID NO:4;        -   iii) a third CDR comprising SEQ ID NO: 5; and    -   b) a light chain variable region comprising:        -   i) a first CDR comprising SEQ ID NO: 6;        -   ii) a second CDR comprising SEQ ID NO:7;        -   iii) a third CDR comprising SEQ ID NO:8.

10. The method according to clause 9, wherein the heavy chain variableregion comprises SEQ ID NO:9.

11. The method according to clause 9, wherein the light chain variableregion comprises SEQ ID NO:10.

12. The method according to any one of clauses 9 to 11, wherein theheavy chain variable region comprises SEQ ID NO:9 and the light chainvariable region comprises SEQ ID NO:10.

13. The method according to any one of clauses 9 to 11, wherein theheavy chain comprises SEQ ID NO:21 and the light chain comprises SEQ IDNO:22.

14. The method according to any one of clauses 1 to 8, wherein theanti-CD38 antibody comprises:

-   -   a) a heavy chain variable region comprising:        -   i) a first CDR comprising SEQ ID NO: 13;        -   ii) a second CDR comprising SEQ ID NO:14;        -   iii) a third CDR comprising SEQ ID NO: 15; and    -   b) a light chain variable region comprising:        -   i) a first CDR comprising SEQ ID NO: 16;        -   ii) a second CDR comprising SEQ ID NO:17;        -   iii) a third CDR comprising SEQ ID NO:18.

15. The method according to clause 14, wherein the heavy chain variableregion comprises SEQ ID NO: 11.

16. The method according to clause 14, wherein the light chain variableregion comprises SEQ ID NO: 12.

17. The method according to any one of clauses 14 to 16, wherein theheavy chain variable region comprises SEQ ID NO:11 and the light chainvariable region comprises SEQ ID NO:12.

18. The method according to any one of clauses 14 to 16, wherein theheavy chain comprises SEQ ID NO:34 and the light chain comprises SEQ IDNO:35.

19. The method according to any one of clauses 9 and 14, wherein theanti-CD38 antibody further comprises an Fc domain.

20. The method according to clause 19, wherein the Fc domain is human.

21. The method according to clause 19, wherein the Fc domain is avariant Fc domain.

22. The method according to any one of clauses 1 to 8, wherein theanti-CD38 antibody interacts with at least K121, F135, Q139, D141, E239,W241, C275, K276, F284, P291 and E292 of SEQ ID NO:1.

23. A method of treating a disease in a patient, the method comprisingadministering a therapeutically effective amount of a first anti-CD38antibody to the patient, wherein the first anti-CD38 antibody is anisolated antibody which specifically binds human CD38 (SEQ ID NO:1), thedisease is an autoimmune disease, and a biological sample obtained fromthe patient prior to treatment with the anti-CD38 antibody was shown tohave an elevated level of CD38-expressing cells relative to a controlsubject by flow cytometry.

24. A method of treating a disease in a patient, the method comprisingadministering a therapeutically effective amount of a first anti-CD38antibody to the patient, wherein the first anti-CD38 antibody is anisolated antibody which specifically binds human CD38 (SEQ ID NO:1), thedisease is an autoimmune disease, and a biological sample obtained fromthe patient following treatment with an anti-CD20 antibody was shown tohave an elevated level of CD38-expressing cells relative to a controlsubject by flow cytometry.

25. The method according to any one of clauses 23 and 24, wherein theCD38-expressing cells were stained with a second anti-CD38 antibodyconjugated to a fluorochrome.

26. The method according to clause 25, wherein the second anti-CD38antibody is the antibody as defined in any one of clauses 14 to 18.

27. The method according to any one of clauses 21 to 24, wherein thefirst anti-CD38 antibody is the antibody as defined in any one ofclauses 9 to 13.

28. The method according to any one of clauses 1 to 27, wherein theautoimmune disease is selected from the group consisting of rheumatoidarthritis, systemic lupus erythematosus, inflammatory bowel disease,ulcerative colitis, graft-versus-host disease, myasthenia gravis,Sjogrens syndrome, multiple sclerosis, and autoimmune thyroditis.

29. The method according to any one of clauses 1 to 27, wherein theautoimmune disease is rheumatoid arthritis.

30. The method according to any one of clauses 1 to 27, wherein theautoimmune disease is systemic lupus erythematosus.

31. A method for assaying CD38-expressing cells in whole blood, themethod comprising:

-   -   a) obtaining a sample of whole blood from a subject, wherein the        sample includes red blood cells, white blood cells and an        anticoagulant;    -   b) lysing the red blood cells to form a treated sample;    -   c) freezing the treated sample to form a frozen sample, wherein        freezing occurs within about 24 hours of obtaining the sample of        whole blood from the subject;    -   d) measuring the amount of CD38-expressing cells in the sample        within about 72 hours of obtaining the sample, wherein the        frozen sample is warmed to room temperature before measuring the        amount of CD38-expressing cells.

32. The method of clause 31, wherein the frozen sample is maintained ata temperature of about −20° C. or less prior to measuring the amount ofCD38-expressing cells.

33. The method according to any one of clauses 1 to 32, wherein theCD38-expressing cells are plasma cells and/or plasmablasts.

34. The method according to any one of clauses 1 to 32, wherein theCD38-expressing cells are plasma cells.

35. The method according to any one of clauses 1 to 32, wherein theCD38-expressing blood cells are plasmablasts.

These and other embodiments, features and potential advantages willbecome apparent with reference to the following description anddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts the CD38 Expression Profile on Lymphoid Lineage Cells,with a star indicating high CD38 expression. CD38 expression has beenidentified on pro-B cells (CD34⁺CD19⁺CD20⁻), activated B cells(CD19⁺CD20⁺), plasma cells (CD138⁺CD19⁻CD20⁻), activated CD4⁺ and CD8⁺ Tcells, NKT cells (CD3⁺CD56⁺) and NK cells (CD56⁺CD16⁺). In addition,CD38 expression is found on lymphoid progenitor cells(CD34⁺CD45RA⁺CD10⁺CD19⁻) but not the lymphoid stem cell. In addition,increased CD38 expression is seen on mature DCs and activated monocytes.

FIG. 2 shows the heavy and light chain sequences of Ab79 and Ab19.

FIG. 3 depicts the sequences of human and cynomolgus CD38.

FIG. 4 shows the epitopes of human CD38 that bind to each of theantibodies, Benchmark 1 and 2, Ab19 and Ab79.

FIG. 5 depicts the increased expression of CD38 in PMBCs from SLEpatients using a commercially available human CD38 antibody.

FIG. 6 depicts the percentage change in cell numbers in cyno monkeys at24 hours after dosing.

FIG. 7 shows the recovery of depletion after a single dose of Ab79.

FIG. 8 shows the results from a single HuSCID mouse in terms ofsignificant reductions of all Ig isotypes after a single dose of Ab79.

FIG. 9 is similar to FIG. 8 for Ab79 depleting activity in HuSCID miceas described in the Examples.

FIG. 10 depicts the significant reduction of the anti-tetanus responsein the HuSCID model upon Ab79 treatment.

FIG. 11 shows, again in the HuSCID model, the significant increase insurvival upon Ab79 treatment, essentially a type of graft versus hostmodel.

FIG. 12 depicts the differences in expression of the CD38 antigen inhuman and mouse PBMCs, using commercial antibodies to each.

FIG. 13 shows the therapeutic effect in an inflammatory setting, inshowing the surrogate mouse anti-CD38 antibody depletes immune cellsfrom peripheral blood.

FIG. 14 shows Ab79 depletes blood plasmablasts (CD38+, CD27+), plasmacells (CD138+, CD27+) and (CD138+, IRF4+).

FIG. 15 shows Ab79 depletes bone marrow derived long-lived plasma cells(CD19−, CD38+, CD138+).

FIG. 16 shows sample collection, culture and experimental endpoints.

FIG. 17 shows sensitivity of ASC to Ab79 in blood of healthy volunteers(FIG. 17 a ) and SLE subjects (FIG. 17 b ) as measured by ELISpot.

FIG. 18 shows Ab79 reduces ASC that produce 9G4 (FIG. 18 a ) and Ro(FIG. 18 b ) autoantibodies.

FIG. 19 shows that plasmablasts and plasma cells (CD45+, CD3−, CD19+,CD27+, CD38+) can be detected in whole blood by flow cytometric analysesusing the methods described herein.

FIG. 20 shows flow cytometric analysis of blood cells preserved by theFix/Freeze method described herein following treatment of healthyvolunteers with Ab79, and shows that Ab79 depletes plasmablasts andplasma cells. (o) Placebo; (9) Ab79 (0.03 mg/kg; (A) Ab79 (0.1 mg/kg);(V) Ab79 (0.3 mg/kg); (n) Ab79 (0.6 mg/kg).

DETAILED DESCRIPTION OF THE INVENTION

Overview

The extracellular domain of CD38 has been shown to possess bifunctionalenzyme activity, having both ADP-ribosyl cyclase as well as ADP-ribosylhydrolase activities. Thus, CD38 can catalyze the conversion of NAD⁺ tocADPR (cyclase) and can further hydrolyze it to ADP-ribose (hydrolase).cADPR is involved in the mobilization of calcium from intracellularstores which is a second messenger activity important for cellularproliferation, differentiation, and apoptosis.

Increased expression of CD38 has been documented in a variety ofdiseases of hematopoietic origin and has been described as a negativeprognostic marker in chronic lymphoblastic leukemia. Such diseasesinclude but are not restricted to, multiple myeloma (Jackson et al.(1988)), chronic lymphoblastic leukemia (Moribito et al. (2001), Jelineket al. (2001), Chevalier et al. (2002), Durig et al. (2002)), B-cellchronic lymphocytic leukemia, acute lymphoblastic leukemia (Keyhani etal (2000)) including B-cell acute lymphocytic leukemia, Waldenstrommacroglobulinemia, primary systemic amyloidosis, mantle-cell lymphoma,pro-lymphocytic/myelocytic leukemia, acute myeloid leukemia (Keyhani etal. (1993)), chronic myeloid leukemia (Marinov et al. (1993)),follicular lymphoma, NK-cell leukemia and plasma-cell leukemia. As such,CD38 provides a useful target in the treatment of diseases of thehematopoietic system.

Several anti-CD38 antibodies are in clinical trials for the treatment ofCD38-associated cancers. Accordingly, antibodies to CD38 withtherapeutic effect and/or diagnostic applications are useful. Theinvention provides two different anti-CD38 sets of CDRs that bind todifferent epitopes of CD38, and which bind both human and cynomolgusforms of CD38, and antibodies that contain these CDRs.

In addition, the present invention shows that anti-CD38 antibodies finduse in the diagnosis and/or treatment of inflammation and/orimmunological disorders associated with activated lymphocytes, includingspecifically autoimmune diseases. As shown herein, CD38 is expressed inimmature hematopoeitic cells, down regulated in mature cells, andre-expressed at high levels in activated lymphocytes and plasma cells.For example, high CD38 expression is seen in activated B cells, plasmacells, activated CD4+ T cells, activated CD8+ T cells, NK cells, NKTcells, mature dendritic cells (DCs) and activated monocytes.

The findings herein are surprising in that the presence ofautoantibodies to CD38 has been associated with diabetes, chronicautoimmune thyroiditis and Graves' disease (see Antonelli et al, Clin.Exp. Immunol. 2001 126:426-431; Mallone et al., Diabetes 50:752 (2001)and Antonelli et al., J. Endocrinol. Invest. 27:695-707 (2004), all ofwhich are incorporated by reference.

Accordingly, the antibodies of the invention find use in the diagnosisand/or treatment of a number of diseases, including, but not limited toautoimmune diseases as discussed below, including but not limited tosystemic lupus erthematosus (SLE), rheumatoid arthritis (RA),inflammatory bowel disease (IBD) and ulcerative colitis.

Thus, for example, patients with high plasma cell content can beselected, such as SLE patients who exhibit high plasma cells, as well asRA patients shown to be unresponsive to CD20 based therapies.

The therapeutic anti-CD38 antibodies of the present invention bind toCD38 positive cells, resulting in depletion of these cells, such asactivated lymphocytes, through multiple mechanisms of action, including,but not limited to, CDC, ADCC and apoptosis pathways, as outlinedherein, leading to the treatment and/or ameoloration of autoimmunediseases.

One advantage, not seen in some of the anti-CD38 antibodies in oncologyclinical testing, is the ability to bind to cynomolgus CD38, as theseprimates find use in preclinical testing, and thus can lead to earlyevaluation of dosing, toxicity, efficacy, etc.

CD38 PROTEINS

Accordingly, the present invention provides isolated anti-CD38antibodies that specifically bind human CD38 protein (and, as describedbelow, additionally and preferably specifically bind primate CD38protein). As is known in the art, CD38 proteins are found in a number ofspecies. Of particular use in the present invention are antibodies thatbind to both the human and primate CD38 proteins, particularly primatesused in clinical testing, such as cynomolgus (Macaca fascicularis, Crabeating macaque, sometimes referred to herein as “cyno”) monkeys. By“human CD38” or “human CD38 antigen” refers to the protein of SEQ IDNO:1 or a functional fraction, such as an epitope, as defined herein. Ingeneral, CD38 possesses a short intracytoplasmic tail, a transmembranedomain, and an extracellular domain, in specific embodiments, theantibodies of the invention bind to the extracellular part of the CD38protein. By “cynomolgus CD38” herein is meant SEQ ID NO:2 which is 92%identical to human CD38.

Synonyms of CD38, include ADP ribosyl cyclase 1, cADPr hydrolase 1,Cd38-rsl, Cyclic ADP-ribose hydrolase 1, 1-19, and NIM-R5 antigen.

In some embodiments, the anti-CD38 Ab79 antibodies of the inventioninteract with CD38 at a number of amino acid residues including K121,F135, Q139, D141, M142, D202, V203, H205, Q236, E239, W241, S274, C275,K276, F284, C287, V288, K289, N290, P291, E292, D293. As outlinedherein, other antibodies that interact with these residues also find usein therapeutic and diagnostic applications.

In some embodiments, the anti-CD38 antibodies of the present inventionoptionally (and in some cases preferably) do not bind to other membersof the CD38 family such as CD157. For example, preferred embodimentsherein do not bind to human CD157 of SEQ ID NO:23 (Genbank accessionNP_004325).

Antibodies

The present invention provides anti-CD38 antibodies, generallytherapeutic and/or diagnostic antibodies as described herein. Antibodiesthat find use in the present invention can take on a number of formatsas described herein, including traditional antibodies as well asantibody derivatives, fragments and mimetics, described below.Essentially, the invention provides antibody structures that contain aset of 6 CDRs as defined herein (including small numbers of amino acidchanges as described below).

Traditional antibody structural units typically comprise a tetramer.Each tetramer is typically composed of two identical pairs ofpolypeptide chains, each pair having one “light” (typically having amolecular weight of about 25 kDa) and one “heavy” chain (typicallyhaving a molecular weight of about 50-70 kDa). Human light chains areclassified as kappa and lambda light chains. Heavy chains are classifiedas mu, delta, gamma, alpha, or epsilon, and define the antibody'sisotype as IgM, IgD, IgG, IgA, and IgE, respectively. IgG has severalsubclasses, including, but not limited to IgG1, IgG2, IgG3, and IgG4.IgM has subclasses, including, but not limited to, IgM1 and IgM2. Thus,“isotype” as used herein is meant any of the subclasses ofimmunoglobulins defined by the chemical and antigenic characteristics oftheir constant regions. The known human immunoglobulin isotypes areIgG1, IgG2, IgG3, IgG4, IgA1, IgA2, IgM1, IgM2, IgD, and IgE. It shouldbe understood that therapeutic antibodies can also comprise hybrids ofisotypes and/or subclasses.

The amino-terminal portion of each chain includes a variable region ofabout 100 to 110 or more amino acids primarily responsible for antigenrecognition. In the variable region, three loops are gathered for eachof the V domains of the heavy chain and light chain to form anantigen-binding site. Each of the loops is referred to as acomplementarity-determining region (hereinafter referred to as a “CDR”),in which the variation in the amino acid sequence is most significant.“Variable” refers to the fact that certain segments of the variableregion differ extensively in sequence among antibodies. Variabilitywithin the variable region is not evenly distributed. Instead, the Vregions consist of relatively invariant stretches called frameworkregions (FRs) of 15-30 amino acids separated by shorter regions ofextreme variability called “hypervariable regions” that are each 9-15amino acids long or longer.

Each VH and VL is composed of three hypervariable regions(“complementary determining regions,” “CDRs”) and four FRs, arrangedfrom amino-terminus to carboxy-terminus in the following order:FR1-CDR1-FR2-CDR2-FR3-CDR3-FR4.

The hypervariable region generally encompasses amino acid residues fromabout amino acid residues 24-34 (LCDR1; “L” denotes light chain), 50-56(LCDR2) and 89-97 (LCDR3) in the light chain variable region and aroundabout 31-35B (HCDR1; “H” denotes heavy chain), 50-65 (HCDR2), and 95-102(HCDR3) in the heavy chain variable region; Kabat et al., SEQUENCES OFPROTEINS OF IMMUNOLOGICAL INTEREST, 5^(th) Ed. Public Health Service,National Institutes of Health, Bethesda, Md. (1991) and/or thoseresidues forming a hypervariable loop (e.g. residues 26-32 (LCDR1),50-52 (LCDR2) and 91-96 (LCDR3) in the light chain variable region and26-32 (HCDR1), 53-55 (HCDR2) and 96-101 (HCDR3) in the heavy chainvariable region; Chothia and Lesk (1987) J. Mol. Biol. 196:901-917.Specific CDRs of the invention are described below.

Throughout the present specification, the Kabat numbering system isgenerally used when referring to a residue in the variable domain(approximately, residues 1-107 of the light chain variable region andresidues 1-113 of the heavy chain variable region) (e.g, Kabat et al.,supra (1991)), with the EU number system used for the Fc region.

The CDRs contribute to the formation of the antigen-binding, or morespecifically, epitope binding site of antibodies. “Epitope” refers to adeterminant that interacts with a specific antigen binding site in thevariable region of an antibody molecule known as a paratope. Epitopesare groupings of molecules such as amino acids or sugar side chains andusually have specific structural characteristics, as well as specificcharge characteristics. A single antigen may have more than one epitope.For example, as shown herein, the two different antibodies referred toherein as “Ab19” and Ab79” bind to different epitopes on the CD38molecule.

The epitope may comprise amino acid residues directly involved in thebinding (also called immunodominant component of the epitope) and otheramino acid residues, which are not directly involved in the binding,such as amino acid residues which are effectively blocked by thespecifically antigen binding peptide; in other words, the amino acidresidue is within the footprint of the specifically antigen bindingpeptide.

Epitopes may be either conformational or linear. A conformationalepitope is produced by spatially juxtaposed amino acids from differentsegments of the linear polypeptide chain. A linear epitope is oneproduced by adjacent amino acid residues in a polypeptide chain.Conformational and nonconformational epitopes may be distinguished inthat the binding to the former but not the latter is lost in thepresence of denaturing solvents.

An epitope typically includes at least 3, and more usually, at least 5or 8-10 amino acids in a unique spatial conformation. Antibodies thatrecognize the same epitope can be verified in a simple immunoassayshowing the ability of one antibody to block the binding of anotherantibody to a target antigen, for example “binning”, as outlined in theExamples. X-Ray crystallography studies as shown in the Examples hasidentified the amino acid residues that bind to the antibodies both ofthe invention (including Ab19 and Ab79) and the prior art (Benchmark 1and Benchmark 2), as shown in FIG. 4 .

In the present invention, Ab79 as outlined in the Examples, interactswith a number of amino acid residues of CD38 including K121, F135, Q139,D141, M142, E239, W241, S274, C275, K276, F284, V288, K289, N290, P291,E292 and D293. It should be noted that these residues are identical inboth human and cyno monkeys, with the exception that S274 is actuallyF274 in cyno. These residues may represent the immunodominant epitopeand/or residues within the footprint of the specifically antigen bindingpeptide.

In the present invention, Ab19 binds to a different epitope, includingG91, E103, E1034, D105, Q107, M110, Kill, T114, Q115, T148, V192, R194,R195, F196, A199, H228, N229, Q231, E233 and K234. It should be notedthat these residues are identical in both human and cyno monkeys, withthe exception that M110 is V110 in cyno and A199 is T199 in cyno.

Thus, in some embodiments, antibodies that compete with Ab79 and Ab19 bybinding at either of these epitopes can be used to treat autoimmunediseases. It should be noted that Ab79 and bench mark 1 (BM1) have someoverlap; thus antibodies that compete with Ab79 and are not BM1 find usein the present invention.

Thus, the present invention provides antibodies that bind to both humanand cyno CD38 and interact with at least 80%, 90%, 95% or 98% of theseresidues. Stated differently, the surface area of the interaction zoneis no more than the area of these residues.

The carboxy-terminal portion of each chain defines a constant regionprimarily responsible for effector function. Kabat et al. collectednumerous primary sequences of the variable regions of heavy chains andlight chains. Based on the degree of conservation of the sequences, theyclassified individual primary sequences into the CDR and the frameworkand made a list thereof (see SEQUENCES OF IMMUNOLOGICAL INTEREST, 5^(th)edition, NIH publication, No. 91-3242, E. A. Kabat et al., entirelyincorporated by reference).

In the IgG subclass of immunoglobulins, there are several immunoglobulindomains in the heavy chain. By “immunoglobulin (Ig) domain” herein ismeant a region of an immunoglobulin having a distinct tertiarystructure. Of interest in the present invention are the heavy chaindomains, including, the constant heavy (CH) domains and the hingedomains. In the context of IgG antibodies, the IgG isotypes each havethree CH regions. Accordingly, “CH” domains in the context of IgG are asfollows: “CH1” refers to positions 118-220 according to the EU index asin Kabat. “CH2” refers to positions 237-340 according to the EU index asin Kabat, and “CH3” refers to positions 341-447 according to the EUindex as in Kabat.

Another type of Ig domain of the heavy chain is the hinge region. By“hinge” or “hinge region” or “antibody hinge region” or “immunoglobulinhinge region” herein is meant the flexible polypeptide comprising theamino acids between the first and second constant domains of anantibody. Structurally, the IgG CH1 domain ends at EU position 220, andthe IgG CH2 domain begins at residue EU position 237. Thus for IgG theantibody hinge is herein defined to include positions 221 (D221 in IgG1)to 236 (G236 in IgG1), wherein the numbering is according to the EUindex as in Kabat. In some embodiments, for example in the context of anFc region, the lower hinge is included, with the “lower hinge” generallyreferring to positions 226 or 230.

Of particular interest in the present invention are the Fc regions. By“Fc” or “Fc region” or “Fc domain” as used herein is meant thepolypeptide comprising the constant region of an antibody excluding thefirst constant region immunoglobulin domain and in some cases, part ofthe hinge. Thus Fc refers to the last two constant region immunoglobulindomains of IgA, IgD, and IgG, the last three constant regionimmunoglobulin domains of IgE and IgM, and the flexible hinge N-terminalto these domains. For IgA and IgM, Fc may include the J chain. For IgG,the Fc domain comprises immunoglobulin domains Cγ2 and Cγ3 (Cγ2 and Cγ3)and the lower hinge region between Cγ1 (Cγ1) and Cγ2 (Cγ2). Although theboundaries of the Fc region may vary, the human IgG heavy chain Fcregion is usually defined to include residues C226 or P230 to itscarboxyl-terminus, wherein the numbering is according to the EU index asin Kabat. In some embodiments, as is more fully described below, aminoacid modifications are made to the Fc region, for example to alterbinding to one or more FcγR receptors or to the FcRn receptor.

In some embodiments, the antibodies are full length. By “full lengthantibody” herein is meant the structure that constitutes the naturalbiological form of an antibody, including variable and constant regions,including one or more modifications as outlined herein.

Alternatively, the antibodies can be a variety of structures, including,but not limited to, antibody fragments, monoclonal antibodies,bispecific antibodies, minibodies, domain antibodies, syntheticantibodies (sometimes referred to herein as “antibody mimetics”),chimeric antibodies, humanized antibodies, antibody fusions (sometimesreferred to as “antibody conjugates”), and fragments of each,respectively. Structures that still rely

In one embodiment, the antibody is an antibody fragment. Specificantibody fragments include, but are not limited to, (i) the Fab fragmentconsisting of VL, VH, CL and CH1 domains, (ii) the Fd fragmentconsisting of the VH and CH1 domains, (iii) the Fv fragment consistingof the VL and VH domains of a single antibody; (iv) the dAb fragment(Ward et al., 1989, Nature 341:544-546, entirely incorporated byreference) which consists of a single variable, (v) isolated CDRregions, (vi) F(ab′)2 fragments, a bivalent fragment comprising twolinked Fab fragments (vii) single chain Fv molecules (scFv), wherein aVH domain and a VL domain are linked by a peptide linker which allowsthe two domains to associate to form an antigen binding site (Bird etal., 1988, Science 242:423-426, Huston et al., 1988, Proc. Natl. Acad.Sci. U.S.A. 85:5879-5883, entirely incorporated by reference), (viii)bispecific single chain Fv (WO 03/11161, hereby incorporated byreference) and (ix) “diabodies” or “triabodies”, multivalent ormultispecific fragments constructed by gene fusion (Tomlinson et. al.,2000, Methods Enzymol. 326:461-479; WO94/13804; Holliger et al., 1993,Proc. Natl. Acad. Sci. U.S.A. 90:6444-6448, all entirely incorporated byreference).

Chimeric and Humanized Antibodies

In some embodiments, the antibody can be a mixture from differentspecies, e.g. a chimeric antibody and/or a humanized antibody. That is,in the present invention, the CDR sets can be used with framework andconstant regions other than those specifically described by sequenceherein.

In general, both “chimeric antibodies” and “humanized antibodies” referto antibodies that combine regions from more than one species. Forexample, “chimeric antibodies” traditionally comprise variable region(s)from a mouse (or rat, in some cases) and the constant region(s) from ahuman. “Humanized antibodies” generally refer to non-human antibodiesthat have had the variable-domain framework regions swapped forsequences found in human antibodies. Generally, in a humanized antibody,the entire antibody, except the CDRs, is encoded by a polynucleotide ofhuman origin or is identical to such an antibody except within its CDRs.The CDRs, some or all of which are encoded by nucleic acids originatingin a non-human organism, are grafted into the beta-sheet framework of ahuman antibody variable region to create an antibody, the specificity ofwhich is determined by the engrafted CDRs. The creation of suchantibodies is described in, e.g., WO 92/11018, Jones, 1986, Nature321:522-525, Verhoeyen et al., 1988, Science 239:1534-1536, all entirelyincorporated by reference. “Backmutation” of selected acceptor frameworkresidues to the corresponding donor residues is often required to regainaffinity that is lost in the initial grafted construct (U.S. Pat. Nos.5,530,101; 5,585,089; 5,693,761; 5,693,762; 6,180,370; 5,859,205;5,821,337; 6,054,297; 6,407,213, all entirely incorporated byreference). The humanized antibody optimally also will comprise at leasta portion of an immunoglobulin constant region, typically that of ahuman immunoglobulin, and thus will typically comprise a human Fcregion. Humanized antibodies can also be generated using mice with agenetically engineered immune system. Roque et al., 2004, Biotechnol.Prog. 20:639-654, entirely incorporated by reference. A variety oftechniques and methods for humanizing and reshaping non-human antibodiesare well known in the art (See Tsurushita & Vasquez, 2004, Humanizationof Monoclonal Antibodies, Molecular Biology of B Cells, 533-545,Elsevier Science (USA), and references cited therein, all entirelyincorporated by reference). Humanization methods include but are notlimited to methods described in Jones et al., 1986, Nature 321:522-525;Riechmann et al., 1988; Nature 332:323-329; Verhoeyen et al., 1988,Science, 239:1534-1536; Queen et al., 1989, Proc Natl Acad Sci, USA86:10029-33; He et al., 1998, J. Immunol. 160: 1029-1035; Carter et al.,1992, Proc Natl Acad Sci USA 89:4285-9, Presta et al., 1997, Cancer Res.57(20):4593-9; Gorman et al., 1991, Proc. Natl. Acad. Sci. USA88:4181-4185; O'Connor et al., 1998, Protein Eng 11:321-8, all entirelyincorporated by reference. Humanization or other methods of reducing theimmunogenicity of nonhuman antibody variable regions may includeresurfacing methods, as described for example in Roguska et al., 1994,Proc. Natl. Acad. Sci. USA 91:969-973, entirely incorporated byreference. In one embodiment, the parent antibody has been affinitymatured, as is known in the art. Structure-based methods may be employedfor humanization and affinity maturation, for example as described inU.S. Ser. No. 11/004,590. Selection based methods may be employed tohumanize and/or affinity mature antibody variable regions, including butnot limited to methods described in Wu et al., 1999, J. Mol. Biol.294:151-162; Baca et al., 1997, J. Biol. Chem. 272(16):10678-10684;Rosok et al., 1996, J. Biol. Chem. 271(37): 22611-22618; Rader et al.,1998, Proc. Natl. Acad. Sci. USA 95: 8910-8915; Krauss et al., 2003,Protein Engineering 16(10):753-759, all entirely incorporated byreference. Other humanization methods may involve the grafting of onlyparts of the CDRs, including but not limited to methods described inU.S. Ser. No. 09/810,510; Tan et al., 2002, J. Immunol. 169:1119-1125;De Pascalis et al., 2002, J. Immunol. 169:3076-3084, all entirelyincorporated by reference.

In one embodiment, the antibodies of the invention can be multispecificantibodies, and notably bispecific antibodies, also sometimes referredto as “diabodies”. These are antibodies that bind to two (or more)different antigens, or different epitopes on the same antigen. Diabodiescan be manufactured in a variety of ways known in the art (Holliger andWinter, 1993, Current Opinion Biotechnol. 4:446-449, entirelyincorporated by reference), e.g., prepared chemically or from hybridhybridomas.

In one embodiment, the antibody is a minibody. Minibodies are minimizedantibody-like proteins comprising a scFv joined to a CH3 domain. Hu etal., 1996, Cancer Res. 56:3055-3061, entirely incorporated by reference.In some cases, the scFv can be joined to the Fc region, and may includesome or the entire hinge region.

The antibodies of the present invention are generally isolated orrecombinant. “Isolated,” when used to describe the various polypeptidesdisclosed herein, means a polypeptide that has been identified andseparated and/or recovered from a cell or cell culture from which it wasexpressed. Ordinarily, an isolated polypeptide will be prepared by atleast one purification step. An “isolated antibody,” refers to anantibody which is substantially free of other antibodies havingdifferent antigenic specificities. For instance, an isolated antibodythat specifically binds to CD38 is substantially free of antibodies thatspecifically bind antigens other than CD38.

An isolated antibody that specifically binds to an epitope, isoform orvariant of human CD38 or cynomolgus CD38 may, however, havecross-reactivity to other related antigens, for instance from otherspecies, such as CD38 species homologs. Moreover, an isolated antibodymay be substantially free of other cellular material and/or chemicals.

Isolated monoclonal antibodies, having different specificities, can becombined in a well defined composition. Thus for example the Ab79 andAb19 can be combined in a single formulation, if desired.

The anti-CD38 antibodies of the present invention specifically bind CD38ligands (e.g. the human and cynomolgus CD38 proteins of SEQ ID NOs:1 and2. “Specific binding” or “specifically binds to” or is “specific for” aparticular antigen or an epitope means binding that is measurablydifferent from a non-specific interaction. Specific binding can bemeasured, for example, by determining binding of a molecule compared tobinding of a control molecule, which generally is a molecule of similarstructure that does not have binding activity. For example, specificbinding can be determined by competition with a control molecule that issimilar to the target.

Specific binding for a particular antigen or an epitope can beexhibited, for example, by an antibody having a KD for an antigen orepitope of at least about 10⁻⁴ M, at least about 10⁻⁵ M, at least about10⁻⁶ M, at least about 10⁻⁷ M, at least about 10⁻⁸ M, at least about10⁻⁹ M, alternatively at least about 10⁻¹⁰ M, at least about 10⁻¹¹ M, atleast about 10⁻¹² M, or greater, where KD refers to a dissociation rateof a particular antibody-antigen interaction. Typically, an antibodythat specifically binds an antigen will have a KD that is 20-, 50-,100-, 500-, 1000-, 5,000-, 10,000- or more times greater for a controlmolecule relative to the antigen or epitope.

Also, specific binding for a particular antigen or an epitope can beexhibited, for example, by an antibody having a KA or Ka for an antigenor epitope of at least 20-, 50-, 100-, 500-, 1000-, 5,000-, 10,000- ormore times greater for the epitope relative to a control, where KA or Karefers to an association rate of a particular antibody-antigeninteraction.

Antibody Modifications

The present invention further provides variant antibodies. That is,there are a number of modifications that can be made to the antibodiesof the invention, including, but not limited to, amino acidmodifications in the CDRs (affinity maturation), amino acidmodifications in the Fc region, glycosylation variants, covalentmodifications of other types, etc.

By “variant” herein is meant a polypeptide sequence that differs fromthat of a parent polypeptide by virtue of at least one amino acidmodification. Amino acid modifications can include substitutions,insertions and deletions, with the former being preferred in many cases.

In general, variants can include any number of modifications, as long asthe function of the protein is still present, as described herein. Thatis, in the case of amino acid variants generated with the CDRs of eitherAb79 or Ab19, for example, the antibody should still specifically bindto both human and cynomolgus CD38. Similarly, if amino acid variants aregenerated with the Fc region, for example, the variant antibodies shouldmaintain the required receptor binding functions for the particularapplication or indication of the antibody.

However, in general, from 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 amino acidsubstitutions are generally utilized as often the goal is to alterfunction with a minimal number of modifications. In some cases, thereare from 1 to 5 modifications, with from 1-2, 1-3 and 1-4 also findinguse in many embodiments.

It should be noted that the number of amino acid modifications may bewithin functional domains: for example, it may be desirable to have from1-5 modifications in the Fc region of wild-type or engineered proteins,as well as from 1 to 5 modifications in the Fv region, for example. Avariant polypeptide sequence will preferably possess at least about 80%,85%, 90%, 95% or up to 98 or 99% identity to the parent sequences (e.g.the variable regions, the constant regions, and/or the heavy and lightchain sequences for Ab79 and/or Ab19). It should be noted that dependingon the size of the sequence, the percent identity will depend on thenumber of amino acids.

By “amino acid substitution” or “substitution” herein is meant thereplacement of an amino acid at a particular position in a parentpolypeptide sequence with another amino acid. For example, thesubstitution S100A refers to a variant polypeptide in which the serineat position 100 is replaced with alanine. By “amino acid insertion” or“insertion” as used herein is meant the addition of an amino acid at aparticular position in a parent polypeptide sequence. By “amino aciddeletion” or “deletion” as used herein is meant the removal of an aminoacid at a particular position in a parent polypeptide sequence.

By “parent polypeptide”, “parent protein”, “precursor polypeptide”, or“precursor protein” as used herein is meant an unmodified polypeptidethat is subsequently modified to generate a variant. In general, theparent polypeptides herein are Ab79 and Ab19. Parent polypeptide mayrefer to the polypeptide itself, compositions that comprise the parentpolypeptide, or the amino acid sequence that encodes it. Accordingly, by“parent Fc polypeptide” as used herein is meant an Fc polypeptide thatis modified to generate a variant, and by “parent antibody” as usedherein is meant an antibody that is modified to generate a variantantibody.

By “wild type” or “WT” or “native” herein is meant an amino acidsequence or a nucleotide sequence that is found in nature, includingallelic variations. A WT protein, polypeptide, antibody, immunoglobulin,IgG, etc. has an amino acid sequence or a nucleotide sequence that hasnot been intentionally modified.

By “variant Fc region” herein is meant an Fc sequence that differs fromthat of a wild-type Fc sequence by virtue of at least one amino acidmodification. Fc variant may refer to the Fc polypeptide itself,compositions comprising the Fc variant polypeptide, or the amino acidsequence.

In some embodiments, one or more amino acid modifications are made inone or more of the CDRs of the antibody (either Ab79 or Ab19). Ingeneral, only 1 or 2 or 3 amino acids are substituted in any single CDR,and generally no more than from 4, 5, 6, 7, 8 9 or 10 changes are madewithin a set of CDRs. However, it should be appreciated that anycombination of no substitutions, 1, 2 or 3 substitutions in any CDR canbe independently and optionally combined with any other substitution.

In some cases, amino acid modifications in the CDRs are referred to as“affinity maturation”. An “affinity matured” antibody is one having oneor more alteration(s) in one or more CDRs which results in animprovement in the affinity of the antibody for antigen, compared to aparent antibody which does not possess those alteration(s). In somecases, although rare, it may be desirable to decrease the affinity of anantibody to its antigen, but this is generally not preferred.

Affinity maturation can be done to increase the binding affinity of theantibody for the antigen by at least about 10% to 50-100-150% or more,or from 1 to 5 fold as compared to the “parent” antibody. Preferredaffinity matured antibodies will have nanomolar or even picomolaraffinities for the target antigen. Affinity matured antibodies areproduced by known procedures. See, for example, Marks et al., 1992,Biotechnology 10:779-783 that describes affinity maturation by variableheavy chain (VH) and variable light chain (VL) domain shuffling. Randommutagenesis of CDR and/or framework residues is described in: Barbas, etal. 1994, Proc. Nat. Acad. Sci, USA 91:3809-3813; Shier et al., 1995,Gene 169:147-155; Yelton et al., 1995, J. Immunol. 155:1994-2004;Jackson et al., 1995, J. Immunol. 154(7):3310-9; and Hawkins et al,1992, J. Mol. Biol. 226:889-896, for example.

Alternatively, amino acid modifications can be made in one or more ofthe CDRs of the antibodies of the invention that are “silent”, e.g. thatdo not significantly alter the affinity of the antibody for the antigen.These can be made for a number of reasons, including optimizingexpression (as can be done for the nucleic acids encoding the antibodiesof the invention).

Thus, included within the definition of the CDRs and antibodies of theinvention are variant CDRs and antibodies; that is, the antibodies ofthe invention can include amino acid modifications in one or more of theCDRs of Ab79 and Ab19. In addition, as outlined below, amino acidmodifications can also independently and optionally be made in anyregion outside the CDRs, including framework and constant regions.

In some embodiments, variant antibodies of Ab79 and Ab19 that arespecific for human CD38 (SEQ ID NO:1) and cynomolgus CD38 (SEQ ID NO:2)is described. This antibody is composed of six CDRs, wherein each CDR ofthis antibody can differ from SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:5, SEQID NO:6, SEQ ID NO:7, and SEQ ID NO:8 by 0, 1, or 2 amino acidsubstitutions. In other embodiments, the variant anti-CD38 antibody iscomposed of six CDRs, wherein each CDR of this antibody can differ fromSEQ ID NO:13, SEQ ID NO:14, SEQ ID NO:15, SEQ ID NO:16, SEQ ID NO:17,and SEQ ID NO:18 by 0, 1, or 2 amino acid substitutions.

In some embodiments, the anti-CD38 antibodies of the invention arecomposed of a variant Fc domain. As is known in the art, the Fc regionof an antibody interacts with a number of Fc receptors and ligands,imparting an array of important functional capabilities referred to aseffector functions. These Fc receptors include, but are not limited to,(in humans) FcγRI (CD64) including isoforms FcγRIa, FcγRIb, and FcγRIc;FcγRII (CD32), including isoforms FcγRIIa (including allotypes H131 andR131), FcγRIIb (including FcγRIIb-1 and FeyRIIb-2), and FcγRIIc; andFcγRIII (CD16), including isoforms FcγRIIIa (including allotypes V158and F158, correlated to antibody-dependent cell cytotoxicity (ADCC)) andFcγRIIIb (including allotypes FcγRIIIb-NA1 and FcγRIIIb-NA2), FcRn (theneonatal receptor), C1q (complement protein involved in complementdependent cytotoxicity (CDC)) and FcRn (the neonatal receptor involvedin serum half-life). Suitable modifications can be made at one or morepositions as is generally outlined, for example in U.S. patentapplication Ser. No. 11/841,654 and references cited therein, US2004/013210, US 2005/0054832, US 2006/0024298, US 2006/0121032, US2006/0235208, US 2007/0148170, U.S. Ser. No. 12/341,769, U.S. Pat. Nos.6,737,056, 7,670,600, 6,086,875 all of which are expressly incorporatedby reference in their entirety, and in particular for specific aminoacid substitutions that increase binding to Fc receptors.

In addition to the modifications outlined above, other modifications canbe made. For example, the molecules may be stabilized by theincorporation of disulphide bridges linking the VH and VL domains(Reiter et al., 1996, Nature Biotech. 14:1239-1245, entirelyincorporated by reference). In addition, there are a variety of covalentmodifications of antibodies that can be made as outlined below.

Covalent modifications of antibodies are included within the scope ofthis invention, and are generally, but not always, donepost-translationally. For example, several types of covalentmodifications of the antibody are introduced into the molecule byreacting specific amino acid residues of the antibody with an organicderivatizing agent that is capable of reacting with selected side chainsor the N- or C-terminal residues.

Cysteinyl residues most commonly are reacted with α-haloacetates (andcorresponding amines), such as chloroacetic acid or chloroacetamide, togive carboxymethyl or carboxyamidomethyl derivatives. Cysteinyl residuesmay also be derivatized by reaction with bromotrifluoroacetone,α-bromo-β-(5-imidozoyl)propionic acid, chloroacetyl phosphate,N-alkylmaleimides, 3-nitro-2-pyridyl disulfide, methyl 2-pyridyldisulfide, p-chloromercuribenzoate, 2-chloromercuri-4-nitrophenol, orchloro-7-nitrobenzo-2-oxa-1,3-diazole and the like.

Histidyl residues are derivatized by reaction with diethylpyrocarbonateat pH 5.5-7.0 because this agent is relatively specific for the histidylside chain. Para-bromophenacyl bromide also is useful; the reaction ispreferably performed in 0.1M sodium cacodylate at pH 6.0.

Lysinyl and amino terminal residues are reacted with succinic or othercarboxylic acid anhydrides. Derivatization with these agents has theeffect of reversing the charge of the lysinyl residues. Other suitablereagents for derivatizing alpha-amino-containing residues includeimidoesters such as methyl picolinimidate; pyridoxal phosphate;pyridoxal; chloroborohydride; trinitrobenzenesulfonic acid;O-methylisourea; 2,4-pentanedione; and transaminase-catalyzed reactionwith glyoxylate.

Arginyl residues are modified by reaction with one or severalconventional reagents, among them phenylglyoxal, 2,3-butanedione,1,2-cyclohexanedione, and ninhydrin. Derivatization of arginine residuesrequires that the reaction be performed in alkaline conditions becauseof the high pKa of the guanidine functional group. Furthermore, thesereagents may react with the groups of lysine as well as the arginineepsilon-amino group.

The specific modification of tyrosyl residues may be made, withparticular interest in introducing spectral labels into tyrosyl residuesby reaction with aromatic diazonium compounds or tetranitromethane. Mostcommonly, N-acetylimidizole and tetranitromethane are used to formO-acetyl tyrosyl species and 3-nitro derivatives, respectively. Tyrosylresidues are iodinated using 125I or 131I to prepare labeled proteinsfor use in radioimmunoassay, the chloramine T method described abovebeing suitable.

Carboxyl side groups (aspartyl or glutamyl) are selectively modified byreaction with carbodiimides (R′—N═C═N—R′), where R and R′ are optionallydifferent alkyl groups, such as 1-cyclohexyl-3-(2-morpholinyl-4-ethyl)carbodiimide or 1-ethyl-3-(4-azonia-4,4-dimethylpentyl) carbodiimide.Furthermore, aspartyl and glutamyl residues are converted to asparaginyland glutaminyl residues by reaction with ammonium ions.

Derivatization with bifunctional agents is useful for crosslinkingantibodies to a water-insoluble support matrix or surface for use in avariety of methods, in addition to methods described below. Commonlyused crosslinking agents include, e.g.,1,1-bis(diazoacetyl)-2-phenylethane, glutaraldehyde,N-hydroxysuccinimide esters, for example, esters with 4-azidosalicylicacid, homobifunctional imidoesters, including disuccinimidyl esters suchas 3,3′-dithiobis (succinimidylpropionate), and bifunctional maleimidessuch as bis-N-maleimido-1,8-octane. Derivatizing agents such asmethyl-3-[(p-azidophenyl)dithio]propioimidate yield photoactivatableintermediates that are capable of forming crosslinks in the presence oflight. Alternatively, reactive water-insoluble matrices such ascynomolgusogen bromide-activated carbohydrates and the reactivesubstrates described in U.S. Pat. Nos. 3,969,287; 3,691,016; 4,195,128;4,247,642; 4,229,537; and 4,330,440, all entirely incorporated byreference, are employed for protein immobilization.

Glutaminyl and asparaginyl residues are frequently deamidated to thecorresponding glutamyl and aspartyl residues, respectively.Alternatively, these residues are deamidated under mildly acidicconditions. Either form of these residues falls within the scope of thisinvention.

Other modifications include hydroxylation of proline and lysine,phosphorylation of hydroxyl groups of seryl or threonyl residues,methylation of the α-amino groups of lysine, arginine, and histidineside chains (T. E. Creighton, Proteins: Structure and MolecularProperties, W. H. Freeman & Co., San Francisco, pp. 79-86 [1983],entirely incorporated by reference), acetylation of the N-terminalamine, and amidation of any C-terminal carboxyl group.

In addition, as will be appreciated by those in the art, labels(including fluorescent, enzymatic, magnetic, radioactive, etc. can allbe added to the antibodies (as well as the other compositions of theinvention).

Glycosylation

Another type of covalent modification is alterations in glycosylation.In another embodiment, the antibodies disclosed herein can be modifiedto include one or more engineered glycoforms. By “engineered glycoform”as used herein is meant a carbohydrate composition that is covalentlyattached to the antibody, wherein said carbohydrate composition differschemically from that of a parent antibody. Engineered glycoforms may beuseful for a variety of purposes, including but not limited to enhancingor reducing effector function. A preferred form of engineered glycoformis afucosylation, which has been shown to be correlated to an increasein ADCC function, presumably through tighter binding to the FcγRIIIareceptor. In this context, “afucosylation” means that the majority ofthe antibody produced in the host cells is substantially devoid offucose, e.g. 90-95-98% of the generated antibodies do not haveappreciable fucose as a component of the carbohydrate moiety of theantibody (generally attached at N297 in the Fc region). Definedfunctionally, afucosylated antibodies generally exhibit at least a 50%or higher affinity to the FcγRIIIa receptor.

Engineered glycoforms may be generated by a variety of methods known inthe art (Umaña et al., 1999, Nat Biotechnol 17:176-180; Davies et al.,2001, Biotechnol Bioeng 74:288-294; Shields et al., 2002, J Biol Chem277:26733-26740; Shinkawa et al., 2003, J Biol Chem 278:3466-3473; U.S.Pat. No. 6,602,684; U.S. Ser. No. 10/277,370; U.S. Ser. No. 10/113,929;PCT WO 00/61739A1; PCT WO 01/29246A1; PCT WO 02/31140A1; PCT WO02/30954A1, all entirely incorporated by reference; (Potelligent®technology [Biowa, Inc., Princeton, NJ]; GlycoMAb® glycosylationengineering technology [Glycart Biotechnology AG, Zurich, Switzerland]).Many of these techniques are based on controlling the level offucosylated and/or bisecting oligosaccharides that are covalentlyattached to the Fc region, for example by expressing an IgG in variousorganisms or cell lines, engineered or otherwise (for example Lec-13 CHOcells or rat hybridoma YB2/0 cells, by regulating enzymes involved inthe glycosylation pathway (for example FUT8 [α1,6-fucosyltranserase]and/or β1-4-N-acetylglucosaminyltransferase III [GnTIII]), or bymodifying carbohydrate(s) after the IgG has been expressed. For example,the “sugar engineered antibody” or “SEA technology” of Seattle Geneticsfunctions by adding modified saccharides that inhibit fucosylationduring production; see for example 20090317869, hereby incorporated byreference in its entirety. Engineered glycoform typically refers to thedifferent carbohydrate or oligosaccharide; thus an antibody can includean engineered glycoform.

Alternatively, engineered glycoform may refer to the IgG variant thatcomprises the different carbohydrate or oligosaccharide. As is known inthe art, glycosylation patterns can depend on both the sequence of theprotein (e.g., the presence or absence of particular glycosylation aminoacid residues, discussed below), or the host cell or organism in whichthe protein is produced. Particular expression systems are discussedbelow.

Glycosylation of polypeptides is typically either N-linked or O-linked.N-linked refers to the attachment of the carbohydrate moiety to the sidechain of an asparagine residue. The tri-peptide sequencesasparagine-X-serine and asparagine-X-threonine, where X is any aminoacid except proline, are the recognition sequences for enzymaticattachment of the carbohydrate moiety to the asparagine side chain.Thus, the presence of either of these tri-peptide sequences in apolypeptide creates a potential glycosylation site. O-linkedglycosylation refers to the attachment of one of the sugarsN-acetylgalactosamine, galactose, or xylose, to a hydroxyamino acid,most commonly serine or threonine, although 5-hydroxyproline or5-hydroxylysine may also be used.

Addition of glycosylation sites to the antibody is convenientlyaccomplished by altering the amino acid sequence such that it containsone or more of the above-described tri-peptide sequences (for N-linkedglycosylation sites). The alteration may also be made by the additionof, or substitution by, one or more serine or threonine residues to thestarting sequence (for O-linked glycosylation sites). For ease, theantibody amino acid sequence is preferably altered through changes atthe DNA level, particularly by mutating the DNA encoding the targetpolypeptide at preselected bases such that codons are generated thatwill translate into the desired amino acids.

Another means of increasing the number of carbohydrate moieties on theantibody is by chemical or enzymatic coupling of glycosides to theprotein. These procedures are advantageous in that they do not requireproduction of the protein in a host cell that has glycosylationcapabilities for N- and O-linked glycosylation. Depending on thecoupling mode used, the sugar(s) may be attached to (a) arginine andhistidine, (b) free carboxyl groups, (c) free sulfhydryl groups such asthose of cysteine, (d) free hydroxyl groups such as those of serine,threonine, or hydroxyproline, (e) aromatic residues such as those ofphenylalanine, tyrosine, or tryptophan, or (f) the amide group ofglutamine. These methods are described in WO 87/05330 and in Aplin andWriston, 1981, CRC Crit. Rev. Biochem., pp. 259-306, both entirelyincorporated by reference.

Removal of carbohydrate moieties present on the starting antibody (e.g.post-translationally) may be accomplished chemically or enzymatically.Chemical deglycosylation requires exposure of the protein to thecompound trifluoromethanesulfonic acid, or an equivalent compound. Thistreatment results in the cleavage of most or all sugars except thelinking sugar (N-acetylglucosamine or N-acetylgalactosamine), whileleaving the polypeptide intact. Chemical deglycosylation is described byHakimuddin et al., 1987, Arch. Biochem. Biophys. 259:52 and by Edge etal., 1981, Anal. Biochem. 118:131, both entirely incorporated byreference. Enzymatic cleavage of carbohydrate moieties on polypeptidescan be achieved by the use of a variety of endo- and exo-glycosidases asdescribed by Thotakura et al., 1987, Meth. Enzymol. 138:350, entirelyincorporated by reference. Glycosylation at potential glycosylationsites may be prevented by the use of the compound tunicamycin asdescribed by Duskin et al., 1982, J. Biol. Chem. 257:3105, entirelyincorporated by reference. Tunicamycin blocks the formation ofprotein-N-glycoside linkages.

Another type of covalent modification of the antibody comprises linkingthe antibody to various nonproteinaceous polymers, including, but notlimited to, various polyols such as polyethylene glycol, polypropyleneglycol or polyoxyalkylenes, in the manner set forth in, for example,2005-2006 PEG Catalog from Nektar Therapeutics (available at the Nektarwebsite) U.S. Pat. Nos. 4,640,835; 4,496,689; 4,301,144; 4,670,417;4,791,192 or 4,179,337, all entirely incorporated by reference. Inaddition, as is known in the art, amino acid substitutions may be madein various positions within the antibody to facilitate the addition ofpolymers such as PEG. See for example, U.S. Publication No.2005/0114037A1, entirely incorporated by reference.

Specific CDR and Variable Region Embodiments

The present invention provides a number of antibodies each with aspecific set of CDRs (including, as outlined above, some amino acidsubstitutions). As outlined above, the antibodies can be defined by setsof 6 CDRs, by variable regions, or by full-length heavy and lightchains, including the constant regions. In addition, as outlined above,amino acid substitutions may also be made. In general, in the context ofchanges within CDRs, due to the relatively short length of the CDRs, theamino acid modifications are generally described in terms of the numberof amino acid modifications that may be made. While this is alsoapplicable to the discussion of the number of amino acid modificationsthat can be introduced in variable, constant or full length sequences,in addition to number of changes, it is also appropriate to define thesechanges in terms of the “% identity”. Thus, as described herein,antibodies included within the invention are 80, 85, 90, 95, 98 or 99%identical to the SEQ ID NOs listed herein.

In the context of the Ab79 antibody, the set of CDRs is as follows: thethree CDRs of the heavy chain encompass HCDR1 SEQ ID NO:3 (HCDR1), SEQID NO:4 (HCDR2), and SEQ ID NO:5 (HCDR3), and the three CDRs of thelight chain encompass SEQ ID NO:6 (LCDR1), SEQ ID NO:7 (LCDR2), and SEQID NO:8 (LCDR3).

In the context of Ab19, the set of CDRs is as follows: HCDR1 (SEQ IDNO:13), HCDR2 (SEQ ID NO:14), and HCDR3 (SEQ ID NO:15), and LCDR1 (SEQID NO:16), LCDR2 (SEQ ID NO:17), and LCDR3 (SEQ ID NO:18).

Specifically excluded from the present invention are the antibodies ofSEQ ID NOs.: 24 and 25 (the heavy and light chains of Benchmark 1) andSEQ ID NOs.: 26 and 27 (the heavy and light chains of Benchmark 2). Itshould be noted that these antibodies are not cross reactive withcynomolgus CD38, discussed below.

The antibodies of the invention are cross reactive with human andcynomolgus CD38 and are thus species cross-reactive antibodies. A“species cross-reactive antibody” is an antibody that has a bindingaffinity for an antigen from a first mammalian species that is nearlythe same as the binding affinity for a homologue of that antigen from asecond mammalian species. Species cross-reactivity can be expressed, forexample, as a ratio of the KD of an antibody for an antigen of the firstmammalian species over the KD of the same antibody for the homologue ofthat antigen from a second mammalian species wherein the ratio is 1.1,1.2, 1.3, 1.4, 1.5, 2, 5, 10, 15, up to 20. Alternatively oradditionally, an antibody is “species cross reactive” when it showstherapeutic or diagnostic efficacy when administered to the secondspecies. Thus, in the present case, the antibodies of the invention arecross reactive with cynomolgus CD38, show preclinical efficacy whenadministered to cynomolgus primates and thus are considered crossreactive.

In some embodiments, antibodies that compete with the antibodies of theinvention (for example, with Ab79 and/or Ab19) for binding to human CD38and/or cynomolgus CD38 are provided, but are not either BM1 or BM2 areincluded. Competition for binding to CD38 or a portion of CD38 by two ormore anti-CD38 antibodies may be determined by any suitable technique,as is known in the art.

Competition in the context of the present invention refers to anydetectably significant reduction in the propensity of an antibody of theinvention (e.g. Ab79 or Ab19) to bind its particular binding partner,e.g. CD38, in the presence of the test compound. Typically, competitionmeans an at least about 10-100% reduction in the binding of an antibodyof the invention to CD38 in the presence of the competitor, as measuredby standard techniques such as ELISA or Biacore® assays. Thus, forexample, it is possible to set criteria for competitiveness wherein atleast about 10% relative inhibition is detected; at least about 15%relative inhibition is detected; or at least about 20% relativeinhibition is detected before an antibody is considered sufficientlycompetitive. In cases where epitopes belonging to competing antibodiesare closely located in an antigen, competition may be marked by greaterthan about 40% relative inhibition of CD38 binding (e.g., at least about45% inhibition, such as at least about 50% inhibition, for instance atleast about 55% inhibition, such as at least about 60% inhibition, forinstance at least about 65% inhibition, such as at least about 70%inhibition, for instance at least about 75% inhibition, such as at leastabout 80% inhibition, for instance at least about 85% inhibition, suchas at least about 90% inhibition, for instance at least about 95%inhibition, or higher level of relative inhibition).

In some cases, one or more of the components of the competitive bindingassays are labeled, as discussed below in the context of diagnosticapplications.

It may also be the case that competition may exist between anti-CD38antibodies with respect to more than one of CD38 epitope, and/or aportion of CD38, e.g. in a context where the antibody-binding propertiesof a particular region of CD38 are retained in fragments thereof, suchas in the case of a well-presented linear epitope located in varioustested fragments or a conformational epitope that is presented insufficiently large CD38 fragments as well as in CD38.

Assessing competition typically involves an evaluation of relativeinhibitory binding using an antibody of the invention, CD38 (eitherhuman or cynomolgus or both), and the test molecule. Test molecules caninclude any molecule, including other antibodies, small molecules,peptides, etc. The compounds are mixed in amounts that are sufficient tomake a comparison that imparts information about the selectivity and/orspecificity of the molecules at issue with respect to the other presentmolecules.

The amounts of test compound, CD38 and antibodies of the invention maybe varied. For instance, for ELISA assessments about 5-50 μg (e.g.,about 10-50 μg, about 20-50 μg, about 5-20 μg, about 10-20 μg, etc.) ofthe anti-CD38 antibody and/or CD38 targets are required to assesswhether competition exists. Conditions also should be suitable forbinding. Typically, physiological or near-physiological conditions(e.g., temperatures of about 20-40° C., pH of about 7-8, etc.) aresuitable for anti-CD38:CD38 binding.

Often competition is marked by a significantly greater relativeinhibition than about 5% as determined by ELISA and/or FACS analysis. Itmay be desirable to set a higher threshold of relative inhibition as acriteria/determinant of what is a suitable level of competition in aparticular context (e.g., where the competition analysis is used toselect or screen for new antibodies designed with the intended functionof blocking the binding of another peptide or molecule binding to CD38(e.g., the natural binding partners of CD38 such as CD31, also calledCD31 antigen, EndoCAM, GPIIA, PECAM-1, platelet/endothelial celladhesion molecule or naturally occurring anti-CD38 antibody).

In some embodiments, the anti-CD38 antibody of the present inventionspecifically binds to one or more residues or regions in CD38 but alsodoes not cross-react with other proteins with homology to CD38, such asBST-1 (bone marrow stromal cell antigen-1) and Mo5, also called CD157.

Typically, a lack of cross-reactivity means less than about 5% relativecompetitive inhibition between the molecules when assessed by ELISAand/or FACS analysis using sufficient amounts of the molecules undersuitable assay conditions.

Inhibition of CD38 Activity

The disclosed antibodies may find use in blocking a ligand-receptorinteraction or inhibiting receptor component interaction. The anti-CD38antibodies of the invention may be “blocking” or “neutralizing.” A“neutralizing antibody” is intended to refer to an antibody whosebinding to CD38 results in inhibition of the biological activity ofCD38, for example its capacity to interact with ligands, enzymaticactivity, signaling capacity and, in particular, it's ability to causeactivated lymphocytes. Inhibition of the biological activity of CD38 canbe assessed by one or more of several standard in vitro or in vivoassays known in the art (see examples below).

“Inhibits binding” or “blocks binding” (for instance when referring toinhibition/blocking of binding of a CD38 binding partner to CD38)encompass both partial and complete inhibition/blocking. Theinhibition/blocking of binding of a CD38 binding partner to CD38 mayreduce or alter the normal level or type of cell signaling that occurswhen a CD38 binding partner binds to CD38 without inhibition orblocking. Inhibition and blocking are also intended to include anymeasurable decrease in the binding affinity of a CD38 binding partner toCD38 when in contact with an anti-CD38 antibody, as compared to theligand not in contact with an anti-CD38 antibody, for instance ablocking of binding of a CD38 binding partner to CD38 by at least about10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 99%, or 100%.

The disclosed anti-CD38 antibodies may also inhibit cell growth.“Inhibits growth” includes any measurable decrease in the cell growthwhen contacted with a an anti-CD38 antibody, as compared to the growthof the same cells not in contact with an anti-CD38 antibody, forinstance an inhibition of growth of a cell culture by at least about10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 99%, or 100%.

In some embodiments, the disclosed anti-CD38 antibodies are able todeplete activated lymphocytes, plasmablasts and plasma cells.“Depletion” in this context means a measurable decrease in blood levels(for example as tested in cyno monkeys) of activated lymphocytes and/orplasma cells as compared to untreated animals. In general, depletions ofat least about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 99%, or 100%are seen. As shown below in the Examples, in addition, one particularadvantage that the antibodies of the present invention exhibit is therecoverability of these cells after dosing; that is, as is known forsome treatments (for example with anti-CD20 antibodies for example),cell depletion can last for long periods of time, causing unwanted sideeffects. As shown herein, the effects on the activated lymphocytesand/or plasma cells are recoverable.

Methods for Producing the Antibodies of the Invention

The present invention further provides methods for producing thedisclosed anti-CD38 antibodies. These methods encompass culturing a hostcell containing isolated nucleic acid(s) encoding the antibodies of theinvention. As will be appreciated by those in the art, this can be donein a variety of ways, depending on the nature of the antibody. In someembodiments, in the case where the antibodies of the invention are fulllength traditional antibodies, for example, a heavy chain variableregion and a light chain variable region under conditions such that anantibody is produced and can be isolated.

In general, nucleic acids are provided that encode the antibodies of theinvention. Such polynucleotides encode for both the variable andconstant regions of each of the heavy and light chains, although othercombinations are also contemplated by the present invention inaccordance with the compositions described herein. The present inventionalso contemplates oligonucleotide fragments derived from the disclosedpolynucleotides and nucleic acid sequences complementary to thesepolynucleotides.

The polynucleotides can be in the form of RNA or DNA. Polynucleotides inthe form of DNA, cDNA, genomic DNA, nucleic acid analogs, and syntheticDNA are within the scope of the present invention. The DNA may bedouble-stranded or single-stranded, and if single stranded, may be thecoding (sense) strand or non-coding (anti-sense) strand. The codingsequence that encodes the polypeptide may be identical to the codingsequence provided herein or may be a different coding sequence, whichsequence, as a result of the redundancy or degeneracy of the geneticcode, encodes the same polypeptides as the DNA provided herein.

In some embodiments, nucleic acid(s) encoding the antibodies of theinvention are incorporated into expression vectors, which can beextrachromosomal or designed to integrate into the genome of the hostcell into which it is introduced. Expression vectors can contain anynumber of appropriate regulatory sequences (including, but not limitedto, transcriptional and translational control sequences, promoters,ribosomal binding sites, enhancers, origins of replication, etc.) orother components (selection genes, etc.), all of which are operablylinked as is well known in the art. In some cases two nucleic acids areused and each put into a different expression vector (e.g. heavy chainin a first expression vector, light chain in a second expressionvector), or alternatively they can be put in the same expression vector.It will be appreciated by those skilled in the art that the design ofthe expression vector(s), including the selection of regulatorysequences may depend on such factors as the choice of the host cell, thelevel of expression of protein desired, etc.

In general, the nucleic acids and/or expression can be introduced into asuitable host cell to create a recombinant host cell using any methodappropriate to the host cell selected (e.g., transformation,transfection, electroporation, infection), such that the nucleic acidmolecule(s) are operably linked to one or more expression controlelements (e.g., in a vector, in a construct created by processes in thecell, integrated into the host cell genome). The resulting recombinanthost cell can be maintained under conditions suitable for expression(e.g. in the presence of an inducer, in a suitable non-human animal, insuitable culture media supplemented with appropriate salts, growthfactors, antibiotics, nutritional supplements, etc.), whereby theencoded polypeptide(s) are produced. In some cases, the heavy chains areproduced in one cell and the light chain in another.

Mammalian cell lines available as hosts for expression are known in theart and include many immortalized cell lines available from the AmericanType Culture Collection (ATCC), Manassas, VA including but not limitedto Chinese hamster ovary (CHO) cells, HEK 293 cells, NSO cells, HeLacells, baby hamster kidney (BHK) cells, monkey kidney cells (COS), humanhepatocellular carcinoma cells (e.g., Hep G2), and a number of othercell lines. Non-mammalian cells including but not limited to bacterial,yeast, insect, and plants can also be used to express recombinantantibodies. In some embodiments, the antibodies can be produced intransgenic animals such as cows or chickens.

General methods for antibody molecular biology, expression,purification, and screening are described, for example, in AntibodyEngineering, edited by Kontermann & Dubel, Springer, Heidelberg, 2001and 2010 Hayhurst & Georgiou, 2001, Curr Opin Chem Biol 5:683-689;Maynard & Georgiou, 2000, Annu Rev Biomed Eng 2:339-76; and Morrison, S.(1985) Science 229:1202.

Applications and Indications

Once made, the antibodies of the invention find use in a variety ofapplications, including diagnosis of CD38-related diseases and treatmentthereof.

CD38 Related Conditions

In one aspect, the invention provides methods of diagnosing and treatinga condition associated with inflammation and immune diseases,particularly diseases associated with activated lymphocytes. As shownherein, CD38 is expressed in immature hematopoeitic cells, downregulated in mature cells, and re-expressed at high levels in activatedlymphocytes and plasma cells. For example, high CD38 expression is seenin activated B cells, plasma cells, activated CD4+ T cells, activatedCD8+ T cells, NK cells, NKT cells, mature dendritic cells (DCs) andactivated monocytes.

The therapeutic anti-CD38 antibodies of the present invention bind toCD38 positive cells, resulting in depletion of these cells, such asactivated lymphocytes, through multiple mechanisms of action, includingboth CDC and ADCC pathways.

Thus, any autoimmune disease that exhibits either increased expressionof CD38 or increased numbers of CD38 expressing cells as a component ofthe disease may be treated using the antibodies of the invention. Theseinclude, but are not limited to, allogenic islet graft rejection,alopecia areata, ankylosing spondylitis, antiphospholipid syndrome,autoimmune Addison's disease, antineutrophil cytoplasmic autoantibodies(ANCA), autoimmune diseases of the adrenal gland, autoimmune hemolyticanemia, autoimmune hepatitis, autoimmune myocarditis, autoimmuneneutropenia, autoimmune oophoritis and orchitis, autoimmunethrombocytopenia, autoimmune urticaria, Behcet's disease, bullouspemphigoid, cardiomyopathy, Castleman's syndrome, celiacspruce-dermatitis, chronic fatigue immune disfunction syndrome, chronicinflammatory demyelinating polyneuropathy, Churg-Strauss syndrome,cicatrical pemphigoid, CREST syndrome, cold agglutinin disease, Crohn'sdisease, dermatomyositis, discoid lupus, essential mixedcryoglobulinemia, factor VIII deficiency, fibromyalgia-fibromyositis,glomerulonephritis, Grave's disease, Guillain-Barre, Goodpasture'ssyndrome, graft-versus-host disease (GVHD), Hashimoto's thyroiditis,hemophilia A, idiopathic pulmonary fibrosis, idiopathic thrombocytopeniapurpura (ITP), IgA neuropathy, IgM polyneuropathies, immune mediatedthrombocytopenia, juvenile arthritis, Kawasaki's disease, lichenplantus, lupus erthematosis, Meniere's disease, mixed connective tissuedisease, multiple sclerosis, type 1 diabetes mellitus, myastheniagravis, pemphigus vulgaris, pernicious anemia, polyarteritis nodosa,polychrondritis, polyglandular syndromes, polymyalgia rheumatica,polymyositis and dermatomyositis, primary agammaglobinulinemia, primarybiliary cirrhosis, psoriasis, psoriatic arthritis, Reynauld'sphenomenon, Reiter's syndrome, rheumatoid arthritis, sarcoidosis,scleroderma, Sjorgen's syndrome, solid organ transplant rejection,stiff-man syndrome, systemic lupus erythematosus, takayasu arteritis,temporal arteristis/giant cell arteritis, thrombotic thrombocytopeniapurpura, ulcerative colitis, uveitis, vasculitides such as dermatitisherpetiformis vasculitis, vitiligo, and Wegner's granulomatosis.

Of particular use in some embodiments are the use of the presentantibodies for the use in the diagnosis and/or treatment of a number ofdiseases, including, but not limited to autoimmune diseases, includingbut not limited to systemic lupus erthematosus (SLE), rheumatoidarthritis (RA), inflammatory bowel disease (IBD), ulcerative colitis,and graft-v-host disease.

Thus, for example, patients with high plasma cell content can beselected, such as SLE patients who exhibit high plasma cells, as well asRA patients shown to be unresponsive to CD20 based therapies.

It is known in the art that certain conditions are associated with cellsthat express CD38, and that certain conditions are associated with theoverexpression, high-density expression, or upregulated expression ofCD38 on the surfaces of cells. Whether a cell population expresses CD38or not can be determined by methods known in the art, for example flowcytometric determination of the percentage of cells in a givenpopulation that are labelled by an antibody that specifically binds CD38or immunohistochemical assays, as are generally described below fordiagnostic applications. For example, a population of cells in whichCD38 expression is detected in about 10-30% of the cells can be regardedas having weak positivity for CD38; and a population of cells in whichCD38 expression is detected in greater than about 30% of the cells canbe regarded as definite positivity for CD38 (as in Jackson et al.(1988), Clin. Exp. Immunol. 72: 351-356), though other criteria can beused to determine whether a population of cells expresses CD38. Densityof expression on the surfaces of cells can be determined using methodsknown in the art, such as, for example, flow cytometric measurement ofthe mean fluorescence intensity of cells that have been fluorescentlylabelled using antibodies that specifically bind CD38.

Antibody Compositions for In Vivo Administration

Formulations of the antibodies used in accordance with the presentinvention are prepared for storage by mixing an antibody having thedesired degree of purity with optional pharmaceutically acceptablecarriers, excipients or stabilizers (Remington's Pharmaceutical Sciences16th edition, Osol, A. Ed. [1980]), in the form of lyophilizedformulations or aqueous solutions. Acceptable carriers, excipients, orstabilizers are nontoxic to recipients at the dosages and concentrationsemployed, and include buffers such as phosphate, citrate, and otherorganic acids; antioxidants including ascorbic acid and methionine;preservatives (such as octadecyldimethylbenzyl ammonium chloride;hexamethonium chloride; benzalkonium chloride, benzethonium chloride;phenol, butyl or benzyl alcohol; alkyl parabens such as methyl or propylparaben; catechol; resorcinol; cyclohexanol; 3-pentanol; and m-cresol);low molecular weight (less than about 10 residues) polypeptides;proteins, such as serum albumin, gelatin, or immunoglobulins;hydrophilic polymers such as polyvinylpyrrolidone; amino acids such asglycine, glutamine, asparagine, histidine, arginine, or lysine;monosaccharides, disaccharides, and other carbohydrates includingglucose, mannose, or dextrins; chelating agents such as EDTA; sugarssuch as sucrose, mannitol, trehalose or sorbitol; salt-formingcounter-ions such as sodium; metal complexes (e.g. Zn-proteincomplexes); and/or non-ionic surfactants such as TWEEN™, PLURONICS™ orpolyethylene glycol (PEG).

The formulation herein may also contain more than one active compound asnecessary for the particular indication being treated, preferably thosewith complementary activities that do not adversely affect each other.For example, it may be desirable to provide antibodies with otherspecificities. Alternatively, or in addition, the composition maycomprise a cytotoxic agent, cytokine, growth inhibitory agent and/orsmall molecule antagonist. Such molecules are suitably present incombination in amounts that are effective for the purpose intended.

The active ingredients may also be entrapped in microcapsules prepared,for example, by coacervation techniques or by interfacialpolymerization, for example, hydroxymethylcellulose orgelatin-microcapsules and poly-(methylmethacylate) microcapsules,respectively, in colloidal drug delivery systems (for example,liposomes, albumin microspheres, microemulsions, nano-particles andnanocapsules) or in macroemulsions. Such techniques are disclosed inRemington's Pharmaceutical Sciences 16th edition, Osol, A. Ed. (1980).

The formulations to be used for in vivo administration should besterile, or nearly so. This is readily accomplished by filtrationthrough sterile filtration membranes.

Sustained-release preparations may be prepared. Suitable examples ofsustained-release preparations include semipermeable matrices of solidhydrophobic polymers containing the antibody, which matrices are in theform of shaped articles, e.g. films, or microcapsules. Examples ofsustained-release matrices include polyesters, hydrogels (for example,poly(2-hydroxyethyl-methacrylate), or poly(vinylalcohol)), polylactides(U.S. Pat. No. 3,773,919), copolymers of L-glutamic acid and .gamma.ethyl-L-glutamate, non-degradable ethylene-vinyl acetate, degradablelactic acid-glycolic acid copolymers such as the LUPRON DEPOT™(injectable microspheres composed of lactic acid-glycolic acid copolymerand leuprolide acetate), and poly-D-(−)-3-hydroxybutyric acid. Whilepolymers such as ethylene-vinyl acetate and lactic acid-glycolic acidenable release of molecules for over 100 days, certain hydrogels releaseproteins for shorter time periods.

When encapsulated antibodies remain in the body for a long time, theymay denature or aggregate as a result of exposure to moisture at 37° C.,resulting in a loss of biological activity and possible changes inimmunogenicity. Rational strategies can be devised for stabilizationdepending on the mechanism involved. For example, if the aggregationmechanism is discovered to be intermolecular S—S bond formation throughthio-disulfide interchange, stabilization may be achieved by modifyingsulfhydryl residues, lyophilizing from acidic solutions, controllingmoisture content, using appropriate additives, and developing specificpolymer matrix compositions.

Administrative Modalities

The antibodies of the invention are administered to a subject, in accordwith known methods, such as intravenous administration as a bolus or bycontinuous infusion over a period of time, by intramuscular,intraperitoneal, intracerobrospinal, subcutaneous, intra-articular,intrasynovial, intrathecal, oral, topical, or inhalation routes.Intravenous or subcutaneous administration of the antibody is preferred.

Treatment Modalities

In the methods of the invention, therapy is used to provide a positivetherapeutic response with respect to a disease or condition. By“positive therapeutic response” is intended an improvement in thedisease or condition, and/or an improvement in the symptoms associatedwith the disease or condition. For example, a positive therapeuticresponse would refer to one or more of the following improvements in thedisease: (1) a reduction in the number of neoplastic cells; (2) anincrease in neoplastic cell death; (3) inhibition of neoplastic cellsurvival; (5) inhibition (i.e., slowing to some extent, preferablyhalting) of tumor growth; (6) an increased patient survival rate; and(7) some relief from one or more symptoms associated with the disease orcondition.

Positive therapeutic responses in any given disease or condition can bedetermined by standardized response criteria specific to that disease orcondition. Tumor response can be assessed for changes in tumormorphology (i.e., overall tumor burden, tumor size, and the like) usingscreening techniques such as magnetic resonance imaging (MRI) scan,x-radiographic imaging, computed tomographic (CT) scan, bone scanimaging, endoscopy, and tumor biopsy sampling including bone marrowaspiration (BMA) and counting of tumor cells in the circulation.

In addition to these positive therapeutic responses, the subjectundergoing therapy may experience the beneficial effect of animprovement in the symptoms associated with the disease.

Thus for B cell tumors, the subject may experience a decrease in theso-called B symptoms, i.e., night sweats, fever, weight loss, and/orurticaria. For pre-malignant conditions, therapy with an anti-CD38therapeutic agent may block and/or prolong the time before developmentof a related malignant condition, for example, development of multiplemyeloma in subjects suffering from monoclonal gammopathy of undeterminedsignificance (MGUS).

An improvement in the disease may be characterized as a completeresponse. By “complete response” is intended an absence of clinicallydetectable disease with normalization of any previously abnormalradiographic studies, bone marrow, and cerebrospinal fluid (CSF) orabnormal monoclonal protein in the case of myeloma.

Such a response may persist for at least 4 to 8 weeks, or sometimes 6 to8 weeks, following treatment according to the methods of the invention.Alternatively, an improvement in the disease may be categorized as beinga partial response. By “partial response” is intended at least about a50% decrease in all measurable tumor burden (i.e., the number ofmalignant cells present in the subject, or the measured bulk of tumormasses or the quantity of abnormal monoclonal protein) in the absence ofnew lesions, which may persist for 4 to 8 weeks, or 6 to 8 weeks.

Treatment according to the present invention includes a “therapeuticallyeffective amount” of the medicaments used. A “therapeutically effectiveamount” refers to an amount effective, at dosages and for periods oftime necessary, to achieve a desired therapeutic result.

A therapeutically effective amount may vary according to factors such asthe disease state, age, sex, and weight of the individual, and theability of the medicaments to elicit a desired response in theindividual. A therapeutically effective amount is also one in which anytoxic or detrimental effects of the antibody or antibody portion areoutweighed by the therapeutically beneficial effects.

A “therapeutically effective amount” for tumor therapy may also bemeasured by its ability to stabilize the progression of disease. Theability of a compound to deplete B-cells may be evaluated in an animalmodel system predictive of efficacy in human autoimmune diseases.

Alternatively, this property of a composition may be evaluated byexamining the ability of the compound to deplete B-cell populations byin vitro assays known to the skilled practitioner. A therapeuticallyeffective amount of a therapeutic compound may deplete B-cellpopulations, or otherwise ameliorate symptoms in a subject. One ofordinary skill in the art would be able to determine such amounts basedon such factors as the subject's size, the severity of the subject'ssymptoms, and the particular composition or route of administrationselected.

Dosage regimens are adjusted to provide the optimum desired response(e.g., a therapeutic response). For example, a single bolus may beadministered, several divided doses may be administered over time or thedose may be proportionally reduced or increased as indicated by theexigencies of the therapeutic situation. Parenteral compositions may beformulated in dosage unit form for ease of administration and uniformityof dosage. Dosage unit form as used herein refers to physically discreteunits suited as unitary dosages for the subjects to be treated; eachunit contains a predetermined quantity of active compound calculated toproduce the desired therapeutic effect in association with the requiredpharmaceutical carrier.

The specification for the dosage unit forms of the present invention aredictated by and directly dependent on (a) the unique characteristics ofthe active compound and the particular therapeutic effect to beachieved, and (b) the limitations inherent in the art of compoundingsuch an active compound for the treatment of sensitivity in individuals.

The efficient dosages and the dosage regimens for the anti-CD38antibodies used in the present invention depend on the disease orcondition to be treated and may be determined by the persons skilled inthe art.

An exemplary, non-limiting range for a therapeutically effective amountof an anti-CD38 antibody used in the present invention is about 0.1-100mg/kg, such as about 0.1-50 mg/kg, for example about 0.1-20 mg/kg, suchas about 0.1-10 mg/kg, for instance about 0.5, about such as 0.3, about1, or about 3 mg/kg. In another embodiment, the antibody is administeredin a dose of 1 mg/kg or more, such as a dose of from 1 to 20 mg/kg, e.g.a dose of from 5 to 20 mg/kg, e.g. a dose of 8 mg/kg.

A medical professional having ordinary skill in the art may readilydetermine and prescribe the effective amount of the pharmaceuticalcomposition required. For example, a physician or a veterinarian couldstart doses of the medicament employed in the pharmaceutical compositionat levels lower than that required in order to achieve the desiredtherapeutic effect and gradually increase the dosage until the desiredeffect is achieved.

In one embodiment, the anti-CD38 antibody is administered by infusion ina weekly dosage of from 10 to 500 mg/kg such as of from 200 to 400 mg/kgSuch administration may be repeated, e.g., 1 to 8 times, such as 3 to 5times. The administration may be performed by continuous infusion over aperiod of from 2 to 24 hours, such as of from 2 to 12 hours.

In one embodiment, the anti-CD38 antibody is administered by slowcontinuous infusion over a long period, such as more than 24 hours, ifrequired to reduce side effects including toxicity.

In one embodiment the anti-CD38 antibody is administered in a weeklydosage of from 250 mg to 2000 mg, such as for example 300 mg, 500 mg,700 mg, 1000 mg, 1500 mg or 2000 mg, for up to 8 times, such as from 4to 6 times. The administration may be performed by continuous infusionover a period of from 2 to 24 hours, such as of from 2 to 12 hours. Suchregimen may be repeated one or more times as necessary, for example,after 6 months or 12 months. The dosage may be determined or adjusted bymeasuring the amount of compound of the present invention in the bloodupon administration by for instance taking out a biological sample andusing anti-idiotypic antibodies which target the antigen binding regionof the anti-CD38 antibody.

In a further embodiment, the anti-CD38 antibody is administered onceweekly for 2 to 12 weeks, such as for 3 to 10 weeks, such as for 4 to 8weeks.

In one embodiment, the anti-CD38 antibody is administered by maintenancetherapy, such as, e.g., once a week for a period of 6 months or more.

In one embodiment, the anti-CD38 antibody is administered by a regimenincluding one infusion of an anti-CD38 antibody followed by an infusionof an anti-CD38 antibody conjugated to a radioisotope. The regimen maybe repeated, e.g., 7 to 9 days later.

As non-limiting examples, treatment according to the present inventionmay be provided as a daily dosage of an antibody in an amount of about0.1-100 mg/kg, such as 0.5, 0.9, 1.0, 1.1, 1.5, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27,28, 29, 30, 40, 45, 50, 60, 70, 80, 90 or 100 mg/kg, per day, on atleast one of day 1, 2,3,4,5,6,7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35,36, 37, 38, 39, or 40, or alternatively, at least one of week 1, 2, 3,4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 afterinitiation of treatment, or any combination thereof, using single ordivided doses of every 24, 12, 8, 6, 4, or 2 hours, or any combinationthereof.

Diagnostic Uses

The anti-CD38 antibodies provided also find use in the in vitro or invivo imaging of tumors or autoimmune disease states associated withCD38. In some embodiments, the antibodies described herein are used forboth diagnosis and treatment, or for diagnosis alone. When anti-CD38antibodies are used for both diagnosis and treatment, some embodimentsrely on two different anti-CD38 antibodies to two different epitopes,such that the diagnostic antibody does not compete for binding with thetherapeutic antibody, although in some cases the same antibody can beused for both. For example, in some instances, the Ab19 antibody is useddiagnostically (generally labeled as discussed below) while Ab79 is usedtherapeutically, or vice versa. Thus included in the invention arecompositions comprising a diagnostic antibody and a therapeuticantibody, and in some embodiments, the diagnostic antibody is labeled asdescribed herein. In addition, the composition of therapeutic anddiagnostic antibodies can also be co-administered with other drugs asoutlined herein.

In many embodiments, a diagnostic antibody is labeled. By “labeled”herein is meant that the antibodies disclosed herein have one or moreelements, isotopes, or chemical compounds attached to enable thedetection in a screen or diagnostic procedure. In general, labels fallinto several classes: a) immune labels, which may be an epitopeincorporated as a fusion partner that is recognized by an antibody, b)isotopic labels, which may be radioactive or heavy isotopes, c) smallmolecule labels, which may include fluorescent and colorimetric dyes(such as fluorescein isothionate, also known as FITC), or molecules suchas biotin that enable other labeling methods, and d) labels such asparticles (including bubbles for ultrasound labeling) or paramagneticlabels that allow body imagining. Labels may be incorporated into theantibodies at any position and may be incorporated in vitro or in vivoduring protein expression, as is known in the art.

Diagnosis can be done either in vivo, by administration of a diagnosticantibody that allows whole body imaging as described below, or in vitro,on a sample or biological sample obtained from a patient. “Sample” or“biological sample” in this context includes any number of things,including, but not limited to, bodily fluids (including, but not limitedto, whole blood, blood plasma, urine, serum, lymph, saliva, anal andvaginal secretions, perspiration and semen), as well as tissue samplessuch as result from biopsies of relevant tissues. In some embodiments,the biological sample is a whole blood sample.

In some embodiments, in vivo imaging is done, including but not limitedto ultrasound, CT scans, X-rays, MRI and PET scans, as well as opticaltechniques, such as those using optical labels for tumors near thesurface of the body.

In vivo imaging of diseases associated with CD38 may be performed by anysuitable technique. For example, ⁹⁹Tc-labeling or labeling with anotherβ-ray emitting isotope may be used to label anti-CD38 antibodies.Variations on this technique may include the use of magnetic resonanceimaging (MRI) to improve imaging over gamma camera techniques. Similarimmunoscintigraphy methods and principles are described in, e.g.,Srivastava (ed.), Radiolabeled Monoclonal Antibodies For Imaging AndTherapy (Plenum Press 1988), Chase, “Medical Applications ofRadioisotopes,” in Remington's Pharmaceutical Sciences, 18th Edition,Gennaro et al., (eds.), pp. 624-652 (Mack Publishing Co., 1990), andBrown, “Clinical Use of Monoclonal Antibodies,” in Biotechnology AndPharmacy 227-49, Pezzuto et al., (eds.) (Chapman & Hall 1993).

In one embodiment, the present invention provides an in vivo imagingmethod wherein an anti-CD38 antibody is conjugated to adetection-promoting agent, the conjugated antibody is administered to ahost, such as by injection into the bloodstream, and the presence andlocation of the labeled antibody in the host is assayed. Through thistechnique and any other diagnostic method provided herein, the presentinvention provides a method for screening for the presence ofdisease-related cells in a human patient or a biological sample takenfrom a human patient.

For diagnostic imaging, radioisotopes may be bound to an anti-CD38antibody either directly, or indirectly by using an intermediaryfunctional group. Useful intermediary functional groups includechelators, such as ethylenediaminetetraacetic acid anddiethylenetriaminepentaacetic acid (see for instance U.S. Pat. No.5,057,313). In such diagnostic assays involving radioisotope-conjugatedanti-CD38 antibodies, the dosage of conjugated anti-CD38 antibodydelivered to the patient typically is maintained at as low a level aspossible through the choice of isotope for the best combination ofminimum half-life, minimum retention in the body, and minimum quantityof isotope, which will permit detection and accurate measurement.

In addition to radioisotopes and radio-opaque agents, diagnostic methodsmay be performed using anti-CD38 antibodies that are conjugated to dyes(such as with the biotin-streptavidin complex), contrast agents,fluorescent compounds (such as fluorescein isothionate, also known asFITC) or molecules and enhancing agents (e.g. paramagnetic ions) formagnetic resonance imaging (MRI) (see, e.g., U.S. Pat. No. 6,331,175,which describes MRI techniques and the preparation of antibodiesconjugated to a MRI enhancing agent). Such diagnostic/detection agentsmay be selected from agents for use in magnetic resonance imaging, andfluorescent compounds.

In order to load an anti-CD38 antibody with radioactive metals orparamagnetic ions, it may be necessary to react it with a reagent havinga long tail to which are attached a multiplicity of chelating groups forbinding the ions. Such a tail may be a polymer such as a polylysine,polysaccharide, or other derivatized or derivatizable chain havingpendant groups to which can be bound chelating groups such as, e.g.,porphyrins, polyamines, crown ethers, bisthiosemicarbazones, polyoximes,and like groups known to be useful for this purpose.

Chelates may be coupled to anti-CD38 antibodies using standardchemistries. A chelate is normally linked to an anti-CD38 antibody by agroup that enables formation of a bond to the molecule with minimal lossof immunoreactivity and minimal aggregation and/or internalcross-linking.

Examples of potentially useful metal-chelate combinations include2-benzyl-DTPA and its monomethyl and cyclohexyl analogs, used withdiagnostic isotopes in the general energy range of 60 to 4,000 keV, suchas ¹²⁵I, ¹²³I, ¹²⁴I, ⁶²Cu, ⁶⁴Cu, ¹⁸F, ¹¹¹In, ⁶⁷Ga, ⁹⁹Tc, ⁹⁴Tc, ¹¹C, ¹³N,⁵O, and ⁷⁶Br, for radio-imaging.

Labels include a radionuclide, a radiological contrast agent, aparamagnetic ion, a metal, a fluorescent label, a chemiluminescentlabel, an ultrasound contrast agent and a photoactive agent. Suchdiagnostic agents are well known and any such known diagnostic agent maybe used. Non-limiting examples of diagnostic agents may include aradionuclide such as ¹¹⁰In, ¹¹¹In, ¹⁷⁷Lu, ¹⁸F, ⁵²Fe, ⁶²Cu, ⁶⁴Cu, ⁶⁷Cu,⁶⁷Ga, ⁶⁸Ga, ⁸⁶Y, ⁹⁰Y, ⁸⁹Zr, ⁹⁴mTc, ⁹⁴Tc, ⁹⁹mTc, ¹²⁰I, ¹²³I, ¹²⁴I, ¹²⁵I,¹³¹I, ¹⁵⁴⁻¹⁵⁸Gd, ³²P, ¹¹C, ¹³N, ¹⁵O, ¹⁸⁶Re, ¹⁸⁸Re, ⁵¹Mn, ⁵²mMn, ⁵⁵Co,⁷²As, ⁷⁵Br, ⁷⁶Br, ⁸²mRb, ⁸³Sr, or other γ-, β-, or positron-emitters.

Paramagnetic ions of use may include chromium (III), manganese (II),iron (III), iron (II), cobalt (II), nickel (II), copper (II), neodymium(III), samarium (III), ytterbium (III), gadolinium (III), vanadium (II),terbium (III), dysprosium (III), holmium (III) or erbium (III). Metalcontrast agents may include lanthanum (III), gold (III), lead (II) orbismuth (III).

Ultrasound contrast agents may comprise liposomes, such as gas filledliposomes. Radiopaque diagnostic agents may be selected from compounds,barium compounds, gallium compounds, and thallium compounds.

These and similar chelates, when complexed with non-radioactive metals,such as manganese, iron, and gadolinium may be useful for MRI diagnosticmethods in connection with anti-CD38 antibodies. Macrocyclic chelatessuch as NOTA, DOTA, and TETA are of use with a variety of metals andradiometals, most particularly with radionuclides of gallium, yttrium,and copper, respectively. Such metal-chelate complexes may be made verystable by tailoring the ring size to the metal of interest. Otherring-type chelates such as macrocyclic polyethers, which are of interestfor stably binding nuclides, such as ²²³Ra may also be suitable indiagnostic methods.

Anti-CD38 antibodies may also be useful in, for example, detectingexpression of an antigen of interest in specific CD38-expressing cells,such as plasmablasts and plains cells, tissues, or serum. In someembodiments, the anti-CD38 antibodies described herein can be useful indetecting expression of an antigen of interest in CD38-expressingplasmablasts and plasma cells. For diagnostic applications, the antibodytypically will be labeled with a detectable moiety for in vitro assays.As will be appreciated by those in the art, there are a wide variety ofsuitable labels for use in in vitro testing. Suitable dyes for use inthis aspect of the invention include, but are not limited to,fluorescent lanthanide complexes, including those of Europium andTerbium, fluorescein, rhodamine, tetramethylrhodamine, eosin,erythrosin, coumarin, methyl-coumarins, quantum dots (also referred toas “nanocrystals”; see U.S. Ser. No. 09/315,584, hereby incorporated byreference), pyrene, Malacite green, stilbene, Lucifer Yellow, CascadeBlue™, Texas Red, Cy dyes (Cy3, Cy5, etc.), alexa dyes (including Alexa,phycoerythin, bodipy, and others described in the 6th Edition of theMolecular Probes Handbook by Richard P. Haugland, hereby expresslyincorporated by reference

Thus, the present invention provides diagnostic anti-CD38 antibodyconjugates, wherein the anti-CD38 antibody conjugate is conjugated to acontrast agent (such as for magnetic resonance imaging, computedtomography, or ultrasound contrast-enhancing agent) or a radionuclidethat may be, for example, a γ-, β-, α-, Auger electron-, orpositron-emitting isotope, or a detectable moiety (such as fluorescein,rhodamine, tetramethylrhodamine, eosin, erythrosin, coumarin, and thelike). In some embodiments, the diagnostic anti-CD38 antibody conjugatein connection with the present invention can be an anti-CD38 antibodyconjugated to fluorescein isothionate, also known as FITC. In someembodiments, the conjugated anti-CD38 antibody can be referred to as ananti-CD38 antibody-fluorescein conjugate. It will be appreciated by oneof skill in the art that other reagents known in the art can be used toconjugate fluorescein to an anti-CD38 antibody, and that in each suchinstance, the resulting conjugate can be referred to as an anti-CD38antibody-fluorescein conjugate. Such anti-CD38 antibody-fluoresceinconjugates as described herein can be used in in vitro assays such asflow cytometry.

Assay Methods

Applicable assay methods for use in connection with the presentinvention include, but are not limited to, flow cytometry, assays forfree “Ig” light chains, mRNA transcript analysis, and the like. It willbe appreciated that any conventional means known in the art forconducting such assay methods may be used in connection with the presentinvention.

In some embodiments, the methods described herein can be carried outusing flow cytometry as a means for quantifying CD38-expressing cells ina biological sample obtained from a patient. It will be appreciated thatas used herein, a biological sample obtained from a patient can be asample of whole blood, a serum sample, or a sample of processed blood.In some embodiments, the biological sample obtained from a patient is awhole blood sample. It will be appreciated that a biological sampleobtained from a patient can include one or more types of cells,including but not limited to red blood cells, and any of the cell typesshown in FIG. 1 . As used herein, “CD38-expressing cells” means anyshown to express CD38, including, but not limited to, pro-B cells(CD34⁺CD19⁺CD20⁻), activated B cells (CD19⁺CD20⁺), plasmablasts(CD19⁺CD27⁺) long-lived plasma cells (CD138⁺CD19-CD20⁻), short-livedplasma cells (CD138⁺CD19⁺CD20⁻), activated CD4⁺ and CD8⁺ T cells, NKTcells (CD3⁺CD56⁺) and NK cells (CD56⁺CD16⁺). In addition, CD38expression is found on lymphoid progenitor cells(CD34⁺CD45RA⁺CD10⁺CD19⁻) but not the lymphoid stem cell. In addition,increased CD38 expression is seen on mature DCs and activated monocytes.

It will be appreciated that flow cytometry can be carried out by anymeans known in the art using any applicable flow cytometry instrument.Such methods include conventional means for sample preparation as arecommonly known in the art in connection with flow cytometry. In someembodiments, the flow cytometry methods are carried out by stainingmethods to assist in differentiating cells in a biological sample. Itwill be appreciated that any staining method commonly known in the artfor use in connection with flow cytometry may be used. In someembodiments, one or more labelled antibodies or antibody conjugates arecontacted with a whole blood sample as described herein. It is wellestablished in the art that multiple cellular targets can be countedusing multicolor flow cytometry. See, for example, Baumgarth, N andRoeder, M, J Immun Methods (2000) 243:77-97. In some embodiments, atleast one labelled antibody or antibody conjugate can be used inconnection with the flow cytometry methods described herein to identifycells contained in the biological sample obtained from a patient. Insome embodiments, at least one labelled antibody or antibody conjugatefor use in connection with the flow cytometry methods described hereinis an anti-CD38 antibody-fluorescein conjugate. In some embodiments, theanti-CD38 antibody-fluorescein conjugate is Ab19-fluorescein orAb79-fluorescein.

In some embodiments, the invention provides for a method of conducting aflow cytometry assay comprising contacting a biological sample obtainedfrom a patient with a lysing/fixing solution (also referred to asresuspending), such as FACS™ Lyse solution, comprising at least onecomponent capable of lysing certain cells, such as red blood cells, andat least one component capable of fixing the sample, such as an aldehydeor alcohol. Suitable components in a lysing/fixing solution capable offixing cells that are useful in connection with the present inventioninclude alcohols, such as methanol or ethanol, which are known to thoseof skill in the art as precipitating or denaturing fixatives capable ofcoagulating proteins, or aldehydes, such as formaldehyde orglutaraldehyde. It will be appreciated that formaldehyde can polymerizeto paraformaldehyde (PFA), and in the presence of methanol, formaldehydemay not polymerize to paraformaldehyde. It will be further appreciatedthat, for applications using alcohol-free formaldehyde as a component inthe lysing/fixing solution, the lysing/fixing may optionally contain abuffer, such as PBS buffer. In some embodiments, the biological sampleis whole blood. In some embodiments, a whole blood sample from a patientcan be contacted with a lysing/fixing solution, such as FACS™ Lysesolution, to lyse red blood cells contained in the whole blood sample.(See, Einwallner, E, Subbasic, A, Strasser, A, et al., J Immun Methods(2013) 390:127-132 and Tiirikainen, M. Cytometry (1995) 20:341-348, bothof which are incorporated herein by reference). In some embodiments, thebiological sample obtained from a patient is contacted with FACS™ Lysesolution to form a treated sample prior to freezing the sample forstorage. In some embodiments, the biological sample obtained from apatient is contacted with FACS™ Lyse solution to form a treated sampleimmediately prior to flow cytometry analysis without freezing thetreated sample for storage. In some embodiments, the biological sampleobtained from a patient can be contacted with FACS™ Lyse solution forfrom about 2 minutes to about 30 minutes. In some embodiments, thebiological sample can be contacted with FACS™ Lyse solution for fromabout 4 minutes to about 20 minutes, or from about 5 minutes to about 10minutes.

In some embodiments, the treated sample obtained after contacting thebiological sample obtained from a patient with a lysing/fixing solution,such as FACS™ Lyse solution, is cooled to a temperature of about −20° C.or less to form a frozen sample. In some embodiments, the treated sampleis cooled to about −80° C. In some embodiments, the treated sample iscooled to about −78° C. In some embodiments, the treated sample iscooled to about −70° C. In some embodiments, the treated sample iscooled to about −60° C. In some embodiments, the treated sample iscooled to about −50° C. In some embodiments, the treated sample iscooled to about −40° C. In some embodiments, the treated sample iscooled to about −30° C. In some embodiments, the treated sample iscooled to about −20° C. In some embodiments, the treated sample iscooled to between about −80° C. and −20° C. In some embodiments, thetreated sample obtained after contacting the biological sample obtainedfrom a patient with a lysing/fixing solution, such as FACS™ Lysesolution, is cooled within about 24 hours or less after the contacting.In some embodiments, the treated sample is cooled within about 12 hoursor less after lysing. In some embodiments, the treated sample is cooledwithin about 6 hours or less.

After the treated sample is frozen, in some embodiments, the frozensample can be warmed to about room temperature prior to enumeratingcells in the biological sample by flow cytometry. In some embodiments,the frozen sample can be warned to about room temperature within about78 hours or less after cooling. In some embodiments, the frozen samplecan be warned to about room temperature within about 72 hours or lessafter cooling. In some embodiments, the frozen sample can be warned toabout room temperature within about 54 hours or less after cooling. Insome embodiments, the frozen sample can be warned to about roomtemperature within about 48 hours or less after cooling. In someembodiments, the frozen sample can be warned to about room temperaturewithin about 30 hours or less after cooling. In some embodiments, thefrozen sample can be warned to about room temperature within about 24hours or less after cooling. In some embodiments, the frozen sample canbe warned to about room temperature within about 72 hours to about 78hours after cooling. In some embodiments, the frozen sample can bewarned to about room temperature within about 48 hours to about 54 hoursafter cooling. In some embodiments, the frozen sample can be warned toabout room temperature within about 24 hours to about 30 hours aftercooling.

In some embodiments, the invention provides a method for assayingCD38-expressing cells in whole blood, the method comprising; obtaining asample of whole blood from a subject, wherein the sample includes redblood cells and an anticoagulant; lysing the red blood cells to form atreated sample; cooling the treated sample to a temperature of about−20° C. or less within about 24 hours of obtaining the sample to form afrozen sample; and measuring the amount of CD38-expressing cells in thesample within about 72 hours of obtaining the sample, wherein the frozensample is warmed to room temperature before measuring the amount ofCD38-expressing cells.

It will be appreciated that changes in the number of plasmablasts orplasma cells present in a biological sample obtained from a patient canbe monitored by assays for free Ig light chains (FLCs). Any assay forfree Ig light chains known to one in the art can be used to measure freeIg light chains, such as the FREELIGHT® assay (BindingSite, UK). See,for example, Fassbinder T, Saunders U, Mickholz E, et al., Arthritis ResTher (2015); Draborg A H, Lydolph M C, Westergaard M, et al., PLoS One(2015) 10(9):e0138753. doi: 10.1371/journal.pone.0138753. eCollection2015. SLE results in a polyclonal activation of plasma cells, patientshave an increase in the kappa and lambda light chains as compared tohealthy subjects and this increase in antibodies and plasma cells isconsidered part of disease pathogenesis (Draborg, 2015). Serum FLC hasbeen reported as marker for SLE and urinary FLC as a marker for ClassIII/IV lupus nephritis. Serum FLC changes with rituximab ormycophenolate mofetil (MMF) treatment and correlates with other bloodplasmablast and plasma cell markers (Fassbinder, 2015; Draborg, 2015).

In some embodiments, the invention provides a method of measuring abiomarker for an elevated expression level of at least one CD38expressing cell-enriched gene in a biological sample obtained from thepatient compared to the expression level of the CD38 expressingcell-enriched gene in a biological sample obtained from a controlsubject. In some embodiments, the invention provides a method ofmeasuring a biomarker for an elevated expression level of a CD38expressing cell-enriched gene in a biological sample obtained from thepatient compared to a threshold value for the CD38 expressingcell-enriched gene. In certain embodiments, the CD38 expressingcell-enriched gene is IgJ. In certain embodiments, the CD38 expressingcell-enriched gene is CD38, In certain embodiments, the biorarkercomprises mRNA In certain embodiments, the biological sample is wholeblood. In some embodiments, the patient has received at least one priortreatment. In some embodiments, the at least one prior treatmentincludes treatment with an anti-CD20 antibody.

In some embodiments, the invention provides a method of predicting theresponse of a patient to a therapy comprising measuring in a biologicalsample obtained from the patient the expression of a biomarker for anelevated expression level of at last one CD38 expressing cell-enrichedgene and comparing the expression of the at least one CD38 expressingcell-enriched gene in the patient's biological sample to the expressionof the same at least one CD38 expressing cell-enriched gene in a.biological sample obtained from a control subject or to a thresholdvalue for the at least one CD38 expressing cell-enriched gene, whereinelevated expression of the at least one CD38 expressing cell-enrichedgene in the patient's biological sample compared to the expression inthe control subject's biological sample or to the threshold value ispredictive of response of the patient to the therapy. In certainembodiments, the plasma cell/plasmablast c-enriched gene is IgJ. Incertain embodiments, measuring the expression of at least one genecomprises measuring mRNA. In a further embodiment, measuring mRNAcomprises a PCR method, RNA sequencing (RNAseq) or a microarray chip. Incertain embodiments, the biological sample comprises whole blood. Insome embodiments, the patient has received at least one prior treatment.In some embodiments, the at least one prior treatment includes treatmentwith an anti-CD20 antibody.

It will be appreciated that the measuring of the expression level of aCD38 expressing cell-enriched gene can be carried out by anyconventional means known in the art. For example, the mRNA level can bemeasured by microarray. In another aspect gene expression is measured bypolymerase chain reaction (PCR), RNAseq or real-time quantitativepolymerase chain reaction (qPCR). In another aspect, gene expression ismeasured by multiplex-PCR. According to another embodiment, expressionof a gene of interest in a patient's biological sample is consideredelevated when compared to that of a control subject's biological sampleif the relative mRNA level of the gene of interest in the patient'ssample is greater than 2 fold of the level of the control subject'snmRNA. According to another embodiment, the relative mRNA level of thegene of interest in the patient's sample is greater than 3 fold, 5 fold,10 fold, 15 fold, 20 fold, 25 fold, or 30 fold compared to the level inthe control subject's sample. In another embodiment, expression of agene of interest in a patient's biological sample is considered low whencompared to that of a control subject's biological sample if therelative mRNA level of the gene of interest in the patient's sample isless than 2 fold of the level of the control subject's mnRNA. Accordingto another embodiment, expression of a gene of interest in a patient'sbiological sample is considered low when compared to that of a controlsubject's biological sample if the relative mRNA level of the gene ofinterest in the patient's sample is less than 3 fold, 5 fold, 10 fold,15 fold, 20 fold, 25 fold, or 30 fold compared to the level in thecontrol subject's sample.

Levels of mRNA may be measured and quantified by various methodswell-known to those skilled in the art, including use of commerciallyavailable kits and reagents. One such method is polymerase chainreaction (PCR). Another method, for quantitative use, is real-timequantitative PCR, or qPCR. See, e.g., Innis M A et al., eds., AcademicPress, Inc. (1990); “Current Protocols in Molecular Biology” (F. M.Ausubel et al., eds., 1987, and periodic updates); and “PCR: ThePolymerase Chain Reaction,” (Mullis et al., eds., 1994). Another methodfor quantitative use is RNAseq. See Wang, Zhong; Gerstein, Mark; Snyder,Michael. “RNA-Seq: a revolutionary tool for transcriptomics”. NatureReviews Genetics 10 (1): 57-63.

In another aspect, the gene expression level is measured by a PCR methodor a microarray method. In one embodiment, the microarray methodcomprises the use of a microarray chip having one or more nucleic acidmolecules that can hybridize under stringent conditions to a nucleicacid molecule encoding a gene mentioned above. In one embodiment, thePCR method is qPCR. In one embodiment, the PCR method is multiplex-PCR.A microarray is a multiplex technology that typically uses an arrayedseries of thousands of nucleic acid probes to hybridize with, e.g, acDNA or cRNA sample under high-stringency conditions. Probe-targethybridization is typically detected and quantified by detection offluorophore-, silver-, or chemiluminescence-labeled targets to determinerelative abundance of nucleic acid sequences in the target. In typicalmicroarrays, the probes are attached to a solid surface by a covalentbond to a chemical matrix (via epoxy-silane, amino-silane, lysine,polyacrylamide or others). The solid surface is for example, glass, asilicon chip, or microscopic beads. Various microarrays are commerciallyavailable, including those manufactured, for example, by Affymetrix,Inc. and Illumina, Inc.

Articles of Manufacture

In other embodiments, an article of manufacture containing materialsuseful for the treatment of the disorders described above is provided.The article of manufacture comprises a container and a label. Suitablecontainers include, for example, bottles, vials, syringes, and testtubes. The containers may be formed from a variety of materials such asglass or plastic. The container holds a composition which is effectivefor treating the condition and may have a sterile access port (forexample the container may be an intravenous solution bag or a vialhaving a stopper pierceable by a hypodermic injection needle). Theactive agent in the composition is the antibody. The label on, orassociated with, the container indicates that the composition is usedfor treating the condition of choice. The article of manufacture mayfurther comprise a second container comprising apharmaceutically-acceptable buffer, such as phosphate-buffered saline,Ringer's solution and dextrose solution. It may further include othermaterials desirable from a commercial and user standpoint, includingother buffers, diluents, filters, needles, syringes, and package insertswith instructions for use.

EXAMPLES

The following examples are offered to illustrate, but not to limit theinvention.

Example 1: Construction of Expression Vectors Comprising PolynucleotidesEncoding Human, Cynomolgus Monkey, and Mouse CD38

To construct a vector expressing human CD38 (huCD38), a polynucleotideencoding huCD38 was isolated from cDNA obtained from OrigeneTechnologies Trueclone® human. The isolated huCD38 was cloned into astable expression vector (XOMA, Inc.) containing the neomycin resistance(neo^(R)) gene, which allowed for the selection of G418(Geneticin)-resistant transfectants. The huCD38 gene present in theselected transfectants was sequenced to identify any sequence errors.Errors in the sequence that deviated from Genbank accession NM_001775were corrected by PCR site-directed mutagenesis. The final vector DNAwas confirmed by 5′ sequencing.

To construct a vector expressing cynomolgus monkey CD38 (cyCD38), apolynucleotide encoding cyCD38 was isolated from DNA obtained fromBiochain Institute's cDNA-monkey (cynomolgus)-normal spleen tissue. Theisolated cyCD38 was cloned into a stable expression vector (XOMA, Inc.)containing the neo^(R) gene, which allowed for the selection of G418(Geneticin)-resistant transfectants. The cyCD38 gene present in theselected transfectants was sequenced to identify any sequence errors.Errors in the sequence that deviated from Genbank accession AY555148were corrected by PCR site directed mutagenesis. The final vector DNAwas confirmed by sequencing.

To construct a vector expressing mouse CD38 (moCD38), a polynucleotideencoding moCD38 was isolated from DNA obtained from Origene's TrueORFcollection. The isolated moCD38 was cloned into a stable expressionvector (XOMA, Inc.) containing the neo^(R) gene, which allowed for theselection of G418 (Geneticin)-resistant transfectants. The moCD38 genepresent in the selected transfectants was sequenced to identify anysequence errors. Errors in the sequence that deviated from Genbankaccession NM_007646 were corrected by PCR site-directed mutagenesis. Thefinal vector DNA was confirmed by sequencing.

Example 2: Development of CD38 Expressing Chinese Hamster Ovary (CHO)Cells

For development of CHO cells expressing huCD38, muCD38 and cyCD38, CHOcells were transfected with linearized DNA. After one week underselection, the cells were sorted by flow cytometry and the highesthuCD38, muCD38 or cyCD38 expressing cells (top 15%) were plated in96-well plates to generate single colonies. The remaining cells werealso plated under selection to generate backup colonies. Approximately12-14 days after plating, single colonies were identified andtransferred to 96-deep-well plates. Clones were screened by FACSanalysis after the second passage. Top producing clones were passagedand expanded to shake flasks. The top 2 clones were frozen and/orcultured for mycoplasmal AVA testing and scale-up.

To construct a luciferase reporter for disseminated xenograft models, acommercial vector containing the CMV promoter/luciferase gene/neomycinselectable marker (Promega, Madison, WI) was used to generate stabletransfectant line in Daudi Burkitt's lymphoma cells.

Example 3: Phage Display Libraries and Screening of Agents that BindCD38

Selection of target specific antibody from a phage display library wascarried out according to methods described by Marks et al. (2004,Methods Mol. Biol. 248:161-76). Briefly, the phage display library wasincubated with 100 pmols of biotinylated CD38 at room temperature for 1hr and the complex formed was then captured using 100 μL of Streptavidinbead suspension (DYNABEADS® M-280 Streptavidin, Invitrogen).Non-specific phages were removed by washing the beads with wash buffer(5% milk in PBS). Bound phages were eluted with 0.5 ml of 100 nMtriethyleamine (TEA) and immediately neutralized by addition of an equalvolume of 1M TRIS-CI, pH 7.4. The eluted phage pool was used to infectTG1 E coli cells growing in logarithmic phase and phagemid was rescuedas described in Marks et al., Id. Selection was repeated for a total ofthree rounds.

Alternatively, phage display libraries were panned against immobilizedCD38 (R&D systems) to identify a panel of antibody fragments with theability to bind CD38. Panning was carried out using standard protocols(see, e.g., Methods in Molecular Biology, vol. 178: Antibody PhageDisplay: Methods and Protocols Edited by: P. M. O'Brien and R. Aitken,Humana Press; “Panning of Antibody Phage-Display Libraries,” Coomber, D.W. J., pp. 133-145, and “Selection of Antibodies Against BiotinylatedAntigens,” Chames et al., pp. 147-157). Briefly, three wells of a NUNC®MAXISORP plate were coated with 50 μL of recombinant CD38 (R&D Systems)at a concentration of 10 μg/ml in PBS. After overnight incubation at 4°C., free binding sites were blocked with 5% milk in PBS for one hour atroom temperature. Approximately 200 μL of phage library in 5% milk/PBSwas then added to the blocked wells and incubated at room temperaturefor approximately one to two hours. Wells were washed and bound phagewas eluted using standard methods (see, e.g., Sam brook and Russell,Molecule Cloning: A Laboratory Manual, 3^(rd) Edition, Cold SpringHarbor Laboratory Press, 2001). Eluted phage was amplified via infectingE. coli TG 1 host cells in logarithmic growth phase. Infected TG 1 cellswere recovered by centrifugation at 2,500 RPM for five minutes, platedonto 15 cm 2YT-ampicillin-2% glucose agar plates, and incubated at 30°C. overnight. The panning process was then repeated using the amplifiedphage. The cycle of panning, elution, and amplification was repeated forthree rounds.

After panning completion, single colonies from the plated TG1 cells wereused to inoculate media in 96-well plates. Microcultures were grown toan OD600 of 0.6, at which point expression of soluble scFv was inducedby addition of 1 mM IPTG and overnight incubation in a shaker at 30° C.Bacteria were pelleted by centrifugation and periplasmic extract wasused to test scFv binding to immobilized CD38 using a standard ELISAassay and a FACS-binding assay.

For FACS binding screen, CHO cells stably expressing CD38 were used toscreen scFvs in periplasmic extract (PPE) for their ability to bindnative, membrane bound CD38. Parental and CHO transfectants (Human CD38or Cyno CD38 or Mouse CD38-expressing cell lines) were resuspendedseparately at 2×10⁶ cells/ml in PBS (Life Technologies), 0.5% BSA(SigmaAldrich), and 0, 1% NaN3 (Sigma-Aldrich) (FACS buffer). ParentalCHO cells not expressing CD38 were used as a negative control. Twentyfive μL aliquots of the cells were plated in Vbottomed 96-well plates(Costar Cat #3897) and 25 μL of periplasmic extract containing myctaggedscFv antibody fragment was added to the cells, then the mixture wasincubated at 4° C. for 30 minutes. The cells were then washed twiceafter which the pellet was resuspended in 25 μL of mouse anti c-myc(1/1000 in FACS buffer)(Roche) and again incubated at 4° C. for 30minutes. The cells were then washed twice and resuspended in 25 μL of1/200 dilution anti-mouse IgG-PE in FACS buffer (Jackson labs) and againincubated at 4° C. for 30 minutes. The cells were then washed twice toremove excess unbound antibody and resuspended in 70 μL FACS buffer andanalysed on a BD FACScan®. The acquired data was evaluated using FlowJosoftware (TreeStar, Inc.). Positive samples were identified by comparingthe median fluorescence intensity of the CD38 transfected CHO cellrelative to the median fluorescence intensity of the parental CHOcell-line (CD38⁻).

Antibody clones that bound human CD38 were sequenced to identify uniqueclones. The unique scFV clones were then ranked based on off-ratesdetermined by Biacore® analysis. 200RU to 500RU of human recombinantCD38 (R&D Systems' cat #2404-AC or equivalent) were immobilized bystandard amine coupling chemistry (Biacore®) to a CM5 or equivalentchip. A reference spot was also prepared which was activated and thenblocked without the immobilization of the protein. This was done bydiluting the antigen to 1-3 μg/ml in acetate buffer, pH 5.0, andinjecting over the activated surface until required level wasimmobilized (3-5) minutes. The surface was then blocked withethanolamine. Periplasmic extracts were diluted one-to-one with theassay running buffer 10 mM HEPES, 150 mM NaCl, 3 mM EDTA(ethylenediaminetetraacetic acid), and 0.05% polysorbate 20 at pH 7.4with 2 mg/mL BSA (bovine serum albumin)). The diluted periplasmicextract was injected over the surface plasmon resonance (SPR) surfacesat 30 minute for 300 seconds with an additional 900 seconds ofdissociation time monitored. Regeneration was with a single 8-secondinjection of 100 mM HCl. Data from the refer˜nce sp,pts were subtractedfrom the data from the active surface, then dissociation curves were fitusing the 1:1 dissociation model in the Biacore® T100 software.

Top-ranking scFV clones were converted to IgG1 antibodies. The FACSbinding screen was repeated on the IgG1 reformatted clones usingparental CHO cells and CHO cells expressing human, murine and cynomolgusCD38 to ensure binding properties were retained and to assess speciescross-reactivity. FACS characterization of IgG-reformatted clones wasconducted as described above, but the steps consisting of the additionof anti-c-myc antibody and anti-mouse IgG-PE were replaced by a singlestep in which binding of full-length human IgG was detected by theaddition of phycoerythrin conjugated anti-human IgG (Jackson Labs).

Example 4: In Vitro Cell-Based Assays of IgG-Reformatted Clones

About 150 clones were reformatted as human IgG1 antibodies and five(Ab19, Ab43, Ab72, Ab79, and Ab110) were fully evaluated using a panelof assays, as described below. Performance of IgG-reformatted clones inboth in vitro and in vivo assays was compared to two antibodies, BMTK4-1(also called benchmark-1, BM-1, or BMTK-1) (SEQ ID NOs:24 and 25; heavyand light chain variable regions) and BMTK4-2 (also called benchmark-2,BM-2, or BMTK-2) (SEQ ID NOs: 26 and 27; heavy and light chain variableregions), the amino acid sequences of which were derived from thesequences of known anti-CD38 antibodies daratumumab (also calledHuMax-CD38, disclosed in International Publication No. WO 06/099875) andSAR650984 (disclosed in International Publication No. WO 08/047242),respectively. Palivizumab (SYNAGIS®) (Medlmmune), a clinically approvedantibody that recognizes respiratory syncytial virus served as anegative control for CD38 binding.

Example 5: Detection of Ab79 Binding by Immunofluorescence

Alexa Fluor®-488 dye labeled Ab79 was applied to frozen sections ofnormal human colorectal tissue, prostate, and lymph. Alexa Fluor®-488dye labeled Palivizumab (Synagis®) served as a negative stainingcontrol. The resulting immunofluorescent images are shown in FIG. 4 .The staining pattern observed for Ab79 was identical to that seen with acommercially available polyclonal anti-CD38 antibody on normal humancolorectal tissue, prostate and lymph node (data not shown).

Alexa Fluor®-488 dye labeled Ab79 was also applied to normal andmultiple myeloma bone marrow specimens (data not shown). Whereas Ab79bound to ˜ 10% of the cells from normal bone marrow, >90% of themultiple myeloma bone marrow cells, in 4 out of 4 tested samples, showedAb79 binding.

The ability of Ab79 to bind to a number of cell lines (MOLP-8, DAUDI,RPMI, and MCF7) was also examined. MOLP-8 (human multiple myeloma),DAUDI (lymphoblast derived from a patient with Burkitt's lymphoma), andRPMI (cell line established from patient with chronic myelogenesisleukemia) cells all showed binding by Ab79. The breast cancer line,MCF7, appeared largely negative for Ab79 binding (data not shown).

The Alexa Fluor® 488-conjugated antibodies were stained on 8 μm cryostatfrozen sections, which were fixed in an ethanol/acetone mixture for 5min followed by incubation with the antibodies for 1 hour at roomtemperature in a humidity-controlled chamber. The sections were thenwashed, a DAPI containing mountant (Vector Laboratories, cat #H1500) wasadded, and a coverslip was applied.

Example 6: Evaluation of Ab79 Expression on Multiple Myeloma (MM) andChronic Lymphocytic Leukemia (CLL)

Ab79 binding to bone marrow samples from multiple myeloma patients wasanalyzed by flow cytometry either after enrichment for CD138′ cells orby gating on CD138⁺CD45^(−/lo) cells (FIG. 7A). Ab79 was found to beexpressed on >95% of cells from four out of six multiple myelomasamples. The binding pattern of Ab79 appeared largely similar to that ofan anti-CD38 antibody used in clinical laboratories. Further, Ab79 boundcells from patients with chronic lymphocytic leukemia (FIG. 7B).

In order to measure Ab79 binding to MM and CLL by FACS patient sampleswere processed within 24 hours. Peripheral blood mononuclear cells wereisolated by Ficoll-Paque™ (GE Healthcare) according to themanufacturer's instructions. Expression analysis was performed using thefollowing panels of antibodies with clones in parentheses. MM panel:Ab79-Alexa Fluor®-488, CD45-PerCP(2D1), CD138-APC (MI15). CLL panel:Ab79-Alexa Fluor®-488; CD5-PE (UCHT2), CD45-PerCP(2D1), CD19-APC(SJ25C1). 5 μL of the PE, PerCP, or APC labeled antibody or 10 μL ofAlexa Fluor®-488 labeled antibody or isotype control was added to eachwell or tube containing either 100 μL of 0.2×106 PBMCs or CD138 enrichedcells from bone marrow aspirate. samples were incubated for 30 mins atroom temperature following which red blood cells were lysed using BDPharmlyse, according to the manufacturer's instructions. All sampleswere washed three times in FACS buffer. Samples were fixed in 1%paraformaldehyde and analyzed on a BD FACSCanto™ II or BD FACSCaliber™.

Example 7: Anti-CD38 Induced CDC Assays

Cynomolgus cross-reactive clones were tested for the ability to inducecomplement-dependent cytotoxicity (CDC). MOLP-8 cells were plated at adensity of 10,000 cells per well in a black 96-well flat-bottom tissueculture plate in 50 μL of complete media (RPMI supplemented with 10%fetal bovine serum). 50 μL of 2× anti-CD38 antibody, control IgGantibody, or media alone was added to each well and left to incubate atroom temperature for 10 min. Varying amounts (2-15 μL) of purifiedrabbit complement (cat #CL 3441 Cedarlane Laboratories, Canada),depending upon the cell line was added to each well except controlwells. After one hour incubation at 37° C., plates were brought to roomtemperature, 100 μL of cell titer CytoTox Glo™ reagent (PromegaG7571/G7573) was added per well, the plate shaken for 5 to 7 min andluminescence read on an EnVision® (Perkin Elmer) luminescence platereader. Conditions tested: cells alone; cells+complement; cells+IgGcontrol+complement; cells+antibody+complement. % CDC was calculatedusing the following equation:

100−(RLU_(T)/RLU_(C))×100),

where RLU_(T) is the relative luminescence units of the test sample andRLU_(C) is the relative luminescence units of the sample with complementalone. Statistical analysis was performed using PRISM software. EC₅₀values, as determined from plots of % CDC versus antibody concentration,are shown in Table 1.

Example 8: Anti-CD38 Induced ADCC Assays

Antibody-dependent cell-mediated cytotoxicity (ADCC) was assessed usingDaudi, MOLP-8, and RPMI-8226 cell lines as target cells. PBMCs wereisolated as effector cells by Ficoll-Plaque™ separation from buffy coator LRS which were obtained from the Stanford Blood Center (Palo Alto,CA). Specimens were diluted 1:3 with 2% FBS in PBS. 15 mL ofFicoll-Plaque™ (GE Healthcare) was gently layered under 35 mL of dilutedspecimen and centrifuged at 1800 rpm (brake off) for 25 min. The cloudyinterphase containing PBMCs was collected, washed 3 times in 2% FBS inPBS and frozen aliquots of 50×106 cells/mL per aliquot in 10% DMSO/FBS.Frozen aliquots of PBMCs were thawed and cultured overnight in 10%FBS/RPMI+5 ng/mL recombinant human IL2 (R & D systems #202-IL) at 2×106per mL, when needed.

For the ADCC assay, all steps were performed in complete media. 5000target cells were plated per well in a 96-well plate in 50 μL of 3×anti-CD38, control IgG, or media alone was added followed by 50 μL ofhuman effector PBMCs at a ration of between 1:25 to 1:50 target:effector(T:E) cells. Plates were briefly centrifuged for ˜ 30 seconds at 800 rpmto bring all cells into close proximity. After 4 hrs at 37° C., plateswere centrifuged at 1100 rpm for 5 min and 100 μL supernatanttransferred to a white plate. 100 μL CytoTox Glo™ reagent (Promega cat#G9292) was added to the supernatant and plates were left to shake for20-30 mins at RT. Luminescence was read on an EnVision® (Perkin Elmer)luminescence plate reader and percent specific lysis was calculatedusing the following equation:

(RLU_(T)/RLU_(E/T))/(RLU_(L)/RLU_(E/T))×100

where RLU_(T) is the relative luminescence units of the test sample andRLU_(E/T) is the relative luminescence units of the sample containingtarget cells and effector cells alone, and RLU_(L) is the relativeluminescence units for cells lysed with Triton X-100. Statisticalanalysis was performed using PRISM software. EC₅₀ values, as determinedfrom plots of % specific lysis versus antibody concentration, are shownin Table 1.

TABLE 1 CDC, ADCC, and Agonist Activity for IgG-Refomatted AntibodiesCDC EC50 nM ADCC EC50 ADCC EC50 ADCC EC50 Apoptosis Antibody (MOLP-8) nM(DAUDI) nM (MOLP-8) nM (RPMI-8226) EC50 nM (DAUDI) BM-1 0.48 ± 0.16 0.03± 0.02 0.036 ± 0.013 0.13 ± 0.03 0.057 BM-2 0.65 ± 0.18 0.04 ± 0.020.024 ± 0.005 0.15 ± 0.04 0.062 Ab19 0.98 ± 0.26 0.08 ± 0.03 0.038 ±0.008 0.46 ± 0.15 0.032 Ab43 2.2 0.12 ± 0.09 0.027 ± 0.018 3.84 ± 1.341.56 Ab72 0.66 ± 0.49 0.14 ± 0.12 0.193 ± 0.037 2.35 ± 0.99 0.35 Ab79 1.1 ± 0.39 0.03 ± 0.02 0.047 ± 0.012 0.46 ± 0.19 0.048 Ab110 1.99 ±0.71 0.24 ± 0.17 0.874 ± 0.804 2.98 ± 0.91 0.40 Ab164 2.00 ± 0.83 ND0.165 ± 0.154  1.2 ± 0.24 0.31

Example 9: Affinity Determination by FACS

MOLP-8 cells expressing CD38 were suspended in 1% FBS buffer at a viablecell concentration of approximately 2 million cells/mL. mAbs to betested were serially diluted (2-fold) across wells over two 96-wellplates in 1×PBS. The last well of each titration contained buffer only.Additional PBS and cell suspensions were added to each well so that thefinal volume was 300˜L/well and each well contained approximately100,000 cells. The mAbs are listed below with the corresponding finalmAb binding site concentration (2× molecular concentration) range usedfor the titrations:

-   -   Benchmark 1, [mAb]bindingsite=50.8 nM-49.7 pM;    -   Benchmark 2, [mAb]bindingsite=49.5 nM-48.3 pM;    -   Ab 43, [mAb]binding site=49.3 nM-48.2 pM;    -   Ab 110, [mAb]bindingsite=204 nM-49.9 pM;    -   Ab 79, [mAb]binding Site=103 nM-25.3 pM;    -   Ab 72, [mAb]binding Site=103 nM-25.2 pM;    -   Ab 19, [mAb]bindingsite=100 nM-12.2 pM;

The plates were placed into a plate shaker for 5 hours at 4° C., afterwhich the plates were washed 3 times at 4° C. with 1×PBS. 200 μl of 99nM Cy5 goat anti-human IgG Fc specific polyclonal antibody (JacksonImmunoResearch Laboratories, #109-175-008) was then added to each well,and the plates were shaken for 30 minutes at 4° C. The plates were againwashed 2× at 4° C. with 1×PBS, then a FACSCanto™ II HTS flow cytometerwas used to record the mean fluorescence intensity (MFI) of 5000 eventsfor each well containing a unique mAb binding site concentration. A plotof the Mean Fluorescence Intensity as a function of the antibody bindingsite concentration was fit nonlinearly with Scientist 3.0 software usingthe equation below to estimate KD:

F=p[(KD+LT+n(M))−{(KD+LT+n(M))2−4n(M)(LT)}1/2]/2+B

where F (mean fluorescence intensity), LT (total mAb binding siteconcentration), p (proportionality constant that relates arbitraryfluorescence units to bound mAb), M (cellular concentration in molarity;0.553 fM based on 100,000 cells in 300 μl), n (number of receptors percell), B (background signal), and KD=equilibrium dissociation constant.

For each antibody titration curve, an estimate for KD was obtained as P,n, B, and KD were floated freely in the nonlinear analysis. For adetailed derivation of the above equation, see Drake and Klakamp (2007),“A rigorous multiple independent binding site model for determiningcell-based equilibrium dissociation constants,” J. Immunol. Methods 318:157-62, which is incorporated by reference herein. Table 3 lists theresulting KD's for all antibodies in order of decreasing affinity alongwith the 95% confidence interval of each fit in parentheses. Theantibody binding site concentration (2× the molecular concentration) wasused for the nonlinear curve-fitting.

Example 10: Affinity Determination by Biacore®

The affinity of IgG antibodies to soluble CD38 ectodomain (ECD) wasdetermined by surface plasmon resonance (SPR) analysis on a Biacore™A100 at 22° C. Goat anti-human IgG polyclonal antibody (Caltag H10500)was immobilized to a CM5 biosensor chip using standard amine coupling tospots 1, 2, 4, and 5 within all four flow cells of the chip.Immobilization levels on each spot ranged from 5865 RU to 6899 RU. HumanCD38 was obtained from R&D Systems (Cat #2404-AC, Lot #PEH020812A). Thestock concentration for CD38 was determined using methods detailed inPace et al. (1995) “How to measure and predict molar absorptioncoefficient of a protein” Protein Science 4(11):2411-23 and Pace andGrimsley (2004) “Spectrophotometric determination of proteinconcentration,” in Current Protocols in Protein Science, Chapter 3: Unit3.1, the teaching of each reference being incorporated by referenceherein.

Running buffer was prepared by degassing HEPES-buffered saline, 0.005%polysorbate 20, and adding filtered BSA to a final concentration of 100μg/mL. All eight purified mAbs were diluted to approximately 2 μg/mLwith running buffer. Preliminary experiments estimated the amount ofeach mAb to be captured in order to maintain a surface capacity(R_(max)) no greater than ˜100 RU. For each mAb capture/antigeninjection cycle, a mAb was captured over spots 1 and 5 within each flowcell with juxtaposed spots 2 and 4 serving as the respective referencesurfaces. Each diluted mAb was captured for 1 minute at a flow rate of10 μL/min followed by three minutes of flowing running buffer forsurface stabilization. HuCD38 was injected over all four flow cells for120 seconds at 30 μL/min over a concentration range of 193.7 nM-3.0 nM(2× serial dilution) followed by a 15 minute dissociation phase. Thesamples were all prepared in the running buffer and were randomlyinjected in triplicate with seven buffer injections interspersed fordouble referencing. The surfaces were regenerated with two 20 secondpulses of 10 mM glycine, pH 1.7.

All sensorgram data were processed with Scrubber 2.0c software andglobally fit to a 1:1 interaction model in Scrubber 2.0c. The resultingbinding constants are shown in Table 2.

TABLE 2 FACS KD FACS KD (nM) (pM) Biacore Ka Biacore Kd Biacore KDAntibody MOLP-8 RPMI-8226 (M−1s−1) (s−1) (nM) BM-1 1.1 (0.9) 802  4.49 ×104  2.46 × 10−3 54.8 BM-2 1.6 (0.6) 428  4.24 × 105  2.27 × 10−3 5.4Ab19 0.4 (0.3) — 1.54 × 10⁵ 8.10 × 10⁻⁴ 5.3 Ab79 1.2 (1.1) 508 1.22 ×10⁵ 6.75 × 10⁻⁴ 5.5 Ab72 0.6 (0.4) — 1.44 × 10⁴ 1.82 × 10⁻³ 126 Ab1101.0 (0.1) — 1.22 × 10⁵ 1.71 × 10⁻¹ 1400 Ab43 1.1 (0.3) — 2.72 × 10⁵ 1.46× 10⁻¹ 537 Ab164 1.4 (0.7) — 1.99 × 10⁵ 7.15 × 10⁻² 359

Example 11: Immunofluorescence Internalization Assays

Immunofluorescence techniques were used to evaluate the internalizationof anti-CD38 antibodies into MOLP-8 cells. MOLP-8 cells were collectedand 5×10⁶ cells were stained for 10 min at 4° C. in RPMI-1640 with 1 μgof each anti-CD38 antibody directly conjugated to Alexa Fluor® 488. Thecells were washed in PBS containing 1% BSA, and 1×10⁶ cells wereincubated for 3 or 6 hours at 4° C. or 37° C. Surface staining wasquenched for 30 min at 4° C. using 2 μg of rabbit anti-Alexa Fluor®-488antibody (Invitrogen). The cells were washed and fixed in PBS with 1%PFA, transferred to a Microtest 96-well plate (BD Biosciences), andeither evaluated by flow cytometry using a FACSCanto™ II (BDBiosciences) flow cytometer or imaged using an ImageXpress® Micro(Molecular Devices) at 20× magnification.

Example 12: Epitope Binning by Biacore®

Biacore® A100 instrumentation was used to bi˜ the two benchmarkantibodies as well as Ab 19 and Ab 79. The antibodies were firstimmobilized at high and low densities on a CM5 chip using NHS/EDCcoupling chemistry. For each cycle of the epitope binning experiment,CD38 was first injected over these surfaces. Analogous to a sandwichassay in an ELISA format, a unique antibody (taken from the set ofimmobilized antibodies) was then injected over surfaces containingCD38/antibody complexes. Surfaces were regenerated using pulses ofphosphoric acid at the end of each cycle. Data was collected at 22° C.using HBS-P (10 mM 10 HEPES pH 7.4, 150 mM NaCI, 0.005%) P-20)supplemented with BSA. The resulting sensorgrams were processed usingthe “Epitope Mapping” module in the Biacore® A100 Evaluation softwarepackage as well as a trial version of Scrubber for A100 data sets.Replicate data was used to generate a binary 4×4 matrix for the above 4mAbs from two separate experiments, as shown in Table 3.

TABLE 3 Ab79 BM1 Ab19 BM2 Ab79 0 0 1 1 BM1 0 0 1 0 Ab19 1 1 0 0 BM2 1 00 0

Example 13: In Vivo Analysis in Oncology

The in vivo efficacy of Ab19 and Ab79 was tested in a disseminatedDaudi-luciferase model of human lymphoma. 6-8 week old female CB.17 SCIDmice from Taconic Laboratories were injected intravenously with 1×10⁶Daudi-Luc tumor cells. At study day 7, mice were treatedintraperitoneally with: palivizumab, Ab 79, Ab19, Benchmark 1, andBenchmark 2. Bioluminescent imaging was performed weekly starting fromday 21 using an IVIS Xenogen system (Caliper Life Sciences) to monitortumor burden. For imaging, animals were injected IP with luciferasesubstrate (150 mg/kg) 10 min before the imaging, then the animals wereanaesthetized under isoflurane and imaged. Results are shown in FIG. 8and FIG. 9 .

Example 14: Inflammatory/Immunological Disease Correlation

CD38 was shown to be dramatically upregulated in PBMC cells followingactivation. In resting PMBCs from normal donors, less than 20% of theresting cells express CD38, with receptor numbers being calculated atroughly 10,000-20,000 per cell. Activated PMBCs, again from normaldonors, showed 60-75% of the cells expressing CD38, with the receptornumbers showing 110,000 to 160,000 per cell.

In addition, as shown in FIG. 5 , CD38 showed increased expression inPMBCs from SLE patients.

Samples were immunohistologically tested for overexpression of CD38. 19samples from SLE patients were analyzed, resulting in the observation ofincreased CD38 expression on B and T memory cells and pDCs. 3 RApatients were analyzed, showing the infiltration of CD38 plasma cells insynovium tissue in all three patients, as well as increased staining ofsynovium tissues with Ab79. 7 Chrohn's Disease patients and 6 ulcerativecolitis patients were analyzed, and showed the infiltration of CD38expressing plasma cells in smooth muscle of the colon (tested on twoprimary cell samples from patients. It should be noted that the samenumber of normal patients were tested without showing these results.

Example 15: Depletion Using Anti-CD38 Antibodies

Dosing cynomolgus monkeys with Ab79 shows a significant decrease inlymphocytes, B and T cells, and NK cells. The antibody was dosed via a30 minute IV infusion at the dosages shown in FIG. 6 , with the databeing collected at 24 hours. Similar data was shown at day 4, 7, 11 and18.

However, the pK/pD data shows the recovery of the animals after dosing.As shown in FIG. 7 , lymphocyte count returned similar to control countsafter a period of days after a single IV 30 minute infusion dose, evenafter the highest dose, indicating that there are no issues with thelymphoid progenitor cells.

Example 16: Autoimmune Disease Models

Three Different Models are Used

A HuScid mouse model served as a pseudo-graft-versus-host model as wellas a model for anti-tetanus response, IgG depletion, and overallsurvival. CB17/HuSCID mice were injected with ASGM1 to deplete NK cells,and then injected with human PBMCs a day later. The engraftment wasallowed to proceed for 7-10 days, with serum collected for human Igrandomization. A day later, the mice were injected with Ab79 at 10 mg/kgfollowed by TTd, with a second dose 4 days later, a third dose 3 daysafter that, with serum collected for human Ig counting and anti-tetanusdetection 3 days after that (total 10 days from first dose). FIG. 8shows the results from a single mouse donor, which indicate significantreductions of all Ig isotypes upon treatment. FIG. 9 shows the resultsof the average Ig levels for each group of recipients, with each datapoint representing the average value per group (n=5 to n=10). FIG. 10shows the significant reduction of the anti-tetanus response upon AB79treatment. Finally, FIG. 11 shows overall significant survival using theAb79 treatment.

Surrogate Mouse Experiments

As Ab79 does not cross react with rodent CD38, a surrogate antibody wasdeveloped. As a preliminary matter, using a commercial antibody to humanCD38 and a commercial antibody to mouse CD38, significant differencesare shown in the CD38 expression levels among cells types between thehuman and mouse (see FIG. 12 ), showing that the biology of disease isdifferent. Thus, using antibodies that cross react with monkey CD38 inmonkey models may give significantly better results.

A surrogate antibody was developed, showing similar depletion of CD38+cells harvested from spleen, blood and bone marrow (data not shown) aswell as from peripheral blood (see FIG. 13 ). In addition, the kineticsof depletion are shown in FIG. 14 , with spleen, blood and bone marrowcollected at 1, 2 or 3 days after a single dose of mouse surrogate at 10mg/kg. A rapid depletion of B cells in blood was shown within 24 hours,with a slower depletion sown in spleen and bone marrow.

Mouse SLE Model

The surrogate mouse anti-CD38 is tested in the MRL/lpr model, using thefollowing interim readouts (for example, every two weeks), from blood:anti-dsDNA autoantibodies, CBC, FACS for T/B cell depletion, proteinalbumin in urine and skin inflammation). Terminal readouts include, butare not limited to, from blood: anti-dsDNA autoantibodies, CBC, FACS forT/B cell depletion, from spleen, lymph nodes and bone marrow: organweight, immune cell numbers, FACS for T/B cell depletion, for kidney:organ weight, histopath (H&E and PAS), IC disposition, inflammatorycells, and skin inflammation (histopath).

Collagen Induced Arthritis (Cia) Model

A mouse CIA model was used using the mouse surrogate antibody, with 7groups of mice to evaluate both pro-prophylatic, prophylatic andtherapeutic efficacy. All mice were immunized with CII/CFA at day 0,with a CII/CFA boost at day 21, generally resulting in diseaseprogression from day 21 to day 42 (study termination). Group 1 (10 mice)was IP injected with 10 mg/kg surrogate antibody twice a week, startingat day 0 (pro-prophylatic). Group 2 (n=10) was similarly dosed butstarting at day 21. Group 3 (n=10) was similarly injected at diseaseonset (day 25-28). Group 4 (n=10) was dosed at the same level but with ahIgG1 (e.g. isotype) at Day 0. Group 5 (n=10) was dosed at the samelevel with hIgG1 but starting at day 21. Group 6)(n=10) was dosed at day21 with 0.5 mg/l water of dexamethasone, and Group 7 (n=5) was nottreated.

A cynomolgus monkey CIA study is done, using n=3 for each group, group 1is naïve animals, vehicle only. Group 2 is a single dose of Ab79 at 3mg/kg or 10 mg/kg, q1w (prophylatic treatment starts at day 7 aftercollagen immunization). Group 3 is Ab79 at 3 mg/kg or 10 mg/kg q1w, fortherapeutic treatment, starting at disease onset, day 21 or day 28.Group 4 is treated with 0.1 mg/kg q1d with dexamethasone at diseaseonset as well.

Example 17: Ab79 Depletes Human Plasma Cells/Plasmablasts In Vitro

In an in vitro culture system using human peripheral blood mononuclearcells (PBMC) or bone marrow mononuclear cells (BMMC), the addition ofAb79 depletes PB/PC populations, which are characterized by the cellsurface expression of CD27, CD38, and CD138 and the intracellular plasmacell markers IRF4 (FIG. 14 ). Ab79 depletes both short-lived plasmacells (CD19+ plasma cells), and long-lived plasma cells (CD19− plasmacells) from bone marrow (FIG. 15 ). Plasma cells and plasmablasts arethe primary antibody secreting cells (ASCs) in the body. See Hibi T andDosch H M. Eur J Immunol (1986) 16(2):139-145. ASCs measured directly byELISpot (FIG. 16 ) are reduced in healthy subject and SLE patientsamples (FIG. 17 ). In samples from healthy subjects in the top panel,Ab79 treatment results in a 70% reduction in the number of IgG producingcells from blood and bone marrow. Similar depletion is seen in SLEpatient samples. Additionally the number of cells producing theautoantigen-specific antibodies VH4-34 9G4+ and anti-Ro are reduced(FIG. 18 ). These results highlight the potential of Ab79 monoclonalantibody as a therapeutic for the treatment for SLE by PB/PC depletion.By targeting CD38, a molecule highly expressed on all PB/PC cells, Ab79effectively depletes both short lived and long-lived ASCs.

Example 18: Detecting PB/PC in Whole Blood Using a Method Suitable forUse in Clinical Setting and in Subjects Treated with Ab79

Flow cytometric analyses of whole blood from a healthy volunteer showsCD38 is highly expressed on PB/PC and that staining using the fix/freezemethod described below with the Ab19 mAb clearly discriminate the CD45+,CD3−, CD19+, CD38+, CD27+ subpopulation of B cells that contains both PBand PC (FIG. 19 a-d ).

Whole blood collected from a healthy volunteer is stained with CD3-PE);CD27-APC; CD45-AF700 CD19-V450; CD38-FITC. For flow cytometric analysiscells are gated to identify single cells, then forward (FSC) vs. sidescatter (SSC) are used to compare blood relative size and granularity(A) and on this basis CD45+staining of mononuclear cells lymphocytes areidentified (B). B cells, within this population, are identified as CD3−CD19+ cells (C). Both plasmablasts and plasma cells are identified asCD27+CD38 bright cells (panel D).

To stain the whole blood samples, tubes containing donor sample aliquotsare centrifuged at 500 RCF for 5 minutes, the supernatant decanted, andthe tubes rack-raked to disperse the cell pellets. The cells are washedwith 2 mL of PBS with 1% BSA, centrifuged at 500 RCF for 5 minutes, thesupernatant decanted, and the tubes rack-raked to disperse the cellpellets. A cell count is taken for each specimen and the cell count isadjusted between 20×10⁶ cells/mL and 40×10⁶ cells/mL with PBS with 1%BSA if necessary. 200 μL is pipetted into the appropriately labeledtube. The appropriate amount of human serum is added to each tube,vortexed and placed in the dark to incubate for 10 minutes. Each tubereceives the appropriate amount of antibodies. All samples are vortexedwell and incubated for 30 minutes at room temperature in the dark. Afterincubation, the cells are washed with 2 mL of PBS with 1% BSA. The tubesare centrifuged at 500 RCF for 5 minutes, supernatant decanted, and thetubes rack-raked to disperse the cell pellets. After centrifugation thecells are reconstituted in 500 μL 1% Paraformaldehyde. The samples areacquired on a BD FACSCantoII Flow Cytometer. Approximately 1,000,000total events are acquired or until 240 seconds had been reached. Thefollowing reagents were are used for staining:

-   -   CD3 PE (Clone: SK7)—BD, Catalog number 347347;    -   CD27 APC (Clone: M-T271)—BD Pharmingen, Catalog number 558664;    -   CD45 AF700 (Clone: HI30)—Biolegend, Catalog number 304024;    -   CD19 V450 (Clone: HIB19)—BD Horizon, Catalog number 560353;    -   CD38 (Ab19);    -   1×FACSLyse;    -   PBS with 1% BSA;    -   1% Paraformaldehyde Solution;    -   Quantum MESF FITC Calibration Beads (LabCorp Analytical        Systems);    -   Quantum MESF APC Calibration Beads (LabCorp Analytical Systems);

Example 19: Comparison of PB/PC Stability in Whole Blood with NoFixative or Treated with FACSLyse and Frozen

Traditional Storage Method and Flow Cytometry

Five healthy donor whole blood specimens are collected into tubescontaining sodium heparin anticoagulant. Samples are tested intriplicate by two independent operators on Day 0 (<2 hourspost-collection). Specimens are then held at ambient temperature andtested in singlet on Day 1 (24-30 hours), Day 2 (48-54 hours), and Day 3(72-48) hours post-collection. Then stained as described for Example 18

Results are shown in Table 4.

TABLE 4 % of CD19+ B cells Day Post- Total Events that are CD38++/ DonorCollection Collected CD27++ Donor 1 0 1104419 0.85 1 226287 0.14 21066353 0.13 3 1094968 0.17 Donor 2 0 885060 0.64 1 232424 0.40 2 6155460.16 3 500499 0.20 Donor 3 0 241812 0.58 1 830574 0.14 2 853470 0.15 3528552 0.07 Donor 4 0 754839 2.23 1 1046385 0.64 2 964089 0.29 3 5772330.27 Donor 5 0 1112831 3.80 1 1098387 0.99 2 1126494 0.61 3 625239 0.42

c. Fix/Freeze Storage Method and Flow Cytometry

Five healthy donor whole blood specimens (sodium heparin anticoagulant)are collected, and the samples are split into four aliquots. The firstaliquot is tested fresh according to the FACSLyse method without afreeze step to establish a baseline measurement of plasmablasts. Thefresh samples are tested in triplicate by two independent operators onDay 0 (<2 hours post-collection). The other three aliquots are frozen at−80° C. after 10 minute incubation with FACSLyse. The second aliquot isthawed in the 38° C. water bath and processed on Day 1 (24-30 hours).The third aliquot is thawed on Day 2 (48-54 hours), and the fourthaliquot on Day 3 (72-78 hours) post-collection. Processing for Days 1-3is performed in singlet.

Frozen aliquots are thawed in a 38° C. water bath until the specimen isfluid in the conical then placed on a sample rocker to complete thethawing process. The tubes are centrifuged at 500 RCF for 5 minutes, thesupernatant decanted, and the tubes rack-raked to disperse the cellpellets. The cells are washed with 2 mL of PBS with 1% BSA, centrifugedat 500 RCF for 5 minutes, the supernatant decanted, and the tubesrack-raked to disperse the cell pellets. A cell count is taken for eachspecimen and the cell count is adjusted between 20×10⁶ cells/mL and40×10⁶ cells/mL with PBS with 1% BSA if necessary. 200 μL is pipettedinto the appropriately labeled tube. The appropriate amount of humanserum is added to each tube, vortexed and placed in the dark to incubatefor 10 minutes. Each tube receives the appropriate amount of antibodies.All samples are vortexed well and incubated for 30 minutes at roomtemperature in the dark. After incubation, the cells are washed with 2mL of PBS with 1% BSA. The tubes are centrifuged at 500 RCF for 5minutes, supernatant decanted, and the tubes rack-raked to disperse thecell pellets. After centrifugation the cells are reconstituted in 500 μL1% Paraformaldehyde. The samples are acquired on a BD FACSCantoII FlowCytometer. Approximately 1,000,000 total events are acquired or until240 seconds are reached. Results are shown in Table 5.

TABLE 5 % of CD19+ B cells Day Post- Total Events that are CD38++/ DonorCollection Collected CD27++ Donor 1 0 1000000 0.14 1 830650 0.10 2908750 0.09 3 737475 0.12 Donor 2 0 230400 0.94 1 794125 1.03 2 6629251.05 3 714550 1.08 Donor 3 0 248500 0.17 1 934225 0.21 2 315400 0.24 3842975 0.20 Donor 4 0 892050 0.32 1 1000000 0.49 2 528175 0.32 3 6006750.24 Donor 5 0 257450 0.48 1 1000000 0.49 2 962875 0.43 3 1000000 0.47

Example 20: Ab79 does not Inhibit Staining with the CD38-Specific mAbAb19

Five healthy donor whole blood specimens (sodium heparin anticoagulant)are collected and spiked with Ab79 (10 μg/mL and zero) for one hour at37° C. After incubation, the samples are split into four aliquots. Thefirst aliquot is tested fresh according to the FACSLyse method without afreeze step to establish a baseline measurement of plasmablasts. Thefresh samples are tested in triplicate by two independent operators onDay 0 (<2 hours post-collection). The other three aliquots are frozen at−80° C. after 10 minute incubation with FACSLyse. The second aliquot isthawed in the 38° C. water bath and processed on Day 1 (24-30 hours).The third aliquot is thawed on Day 2 (48-54 hours), and the fourthaliquot on Day 3 (72-78 hours) post-collection. Processing for Days 1-3is performed in singlet.

Frozen aliquots are thawed in a 38° C. water bath until the specimen isfluid in the conical then placed on a sample rocker to complete thethawing process. The tubes are centrifuged at 500 RCF for 5 minutes, thesupernatant decanted, and the tubes rack-raked to disperse the cellpellets. The cells are washed with 2 mL of PBS with 1% BSA, centrifugedat 500 RCF for 5 minutes, the supernatant decanted, and the tubesrack-raked to disperse the cell pellets. A cell count is taken for eachspecimen and the cell count is adjusted between 20×10⁶ cells/mL and40×10⁶ cells/mL with PBS with 1% BSA if necessary. 200 μL is pipettedinto the appropriately labeled tube. The appropriate amount of humanserum is added to each tube, vortexed and placed in the dark to incubatefor 10 minutes. Each tube receives the appropriate amount of antibodies.All samples are vortexed well and incubated for 30 minutes at roomtemperature in the dark. After incubation, the cells are washed with 2mL of PBS with 1% BSA. The tubes are centrifuged at 500 RCF for 5minutes, supernatant decanted, and the tubes rack-raked to disperse thecell pellets. After centrifugation the cells are reconstituted in 500 μL1% Paraformaldehyde. The samples are acquired on a BD FACSCantoII FlowCytometer. Approximately 1,000,000 total events are acquired or until240 seconds is reached. Results are shown in Table 6.

TABLE 6 % of CD19+ B Total cells that are % of B cells Events CD38++/Total (CD19+) that Collected CD27++ Events are CD38++/ Healthy In thepresence of Collected CD27++ Blood donors 10 microgram/ml Ab79 No Ab79added Donor 1 1000000 0.14 1000000 0.14 Donor 2 818625 0.86 230400 0.94Donor 3 247425 0.18 248500 0.17 Donor 4 255675 0.28 892050 0.32 Donor 5255400 0.48 257450 0.48

Example 21: Healthy Subjects Treated with Ab79 Exhibit a Dose-DependentReduction in PB/PC as Measured Using the Fix/Freeze Method and FlowCytometric Analyses

PB/PC levels are evaluated in highest dose cohorts of Ab79 randomized,double-blind, placebo-controlled, single-dose study in healthy subjects.Ab79 or placebo is administered either as a 2-hour IV infusion or as aSC administration at multiple dose levels. Whole blood is collected at aclinical site. Samples collected prior to treatment (2 screening times,Day −1 and pre-dose Day 1) are used to establish a baseline. Posttreatment samples are collected at 14 time points over a time period of1 hour up to 78 days depending upon route of administration. Themajority of PB/PC data is collected in subjects treated SC. All samplesare preserved using the Fix/Freeze method described above and areanalyzed using multicolor flow cytometric analyses.

Comparison of the median blood PB/PC cell counts in SC treated subjectsshowed that after placebo treatment there are variations in PB/PC levelsover time but treatment with Ab79 results in a consistent decrease ofPB/PC in Ab79 treatment group that lasts for up to 20 days. Results areshown in FIG. 20 .

SEQUENCE LISTING (CD38 Homo sapiens; NP_001766.2) SEQ ID NO: 1MANCEFSPVSGDKPCCRLSRRAQLCLGVSILVLILVVVLAVVVPRWRQQWSGPGTTKRFPETVLARCVKYTEIHPEMRHVDCQSVWDAFKGAFISKHPCNITEEDYQPLMKLGTQTVPCNKILLWSRIKDLAHQFTQVQRDMFTLEDTLLGYLADDLTWCGEFNTSKINYQSCPDWRKDCSNNPVSVFWKTVSRRFAEAACDVVHVMLNGSRSKIFDKNSTFGSVEVHNLQPEKVQTLEAWVIHGGREDSRDLCQDPTIKELESIISKRNIQFSCKNIYR PDKFLQCVKNPEDSSCTSEI(CD38 Macaca fascicularis; AAT36330.1) SEQ ID NO: 2MANCEFSPVSGDKPCCRLSRRAQVCLGVCLLVLLILVVVVAVVLPRWRQQWSGSGTTSRFPETVLARCVKYTEVHPEMRHVDCQSVWDAFKGAFISKYPCNITEEDYQPLVKLGTQTVPCNKTLLWSRIKDLAHQFTQVQRDMFTLEDMLLGYLADDLTWCGEFNTFEINYQSCPDWRKDCSNNPVSVFWKTVSRRFAETACGVVHVMLNGSRSKIFDKNSTFGSVEVHNLQPEKVQALEAWVIHGGREDSRDLCQDPTIKELESIISKRNIRFFCKNIY RPDKFLQCVKNPEDSSCLSGI(HCDR1 Ab79) SEQ ID NO: 3 GFTFDDYG (HCDR2 Ab79) SEQ ID NO: 4 ISWNGGKT(HCDR3 Ab79) SEQ ID NO: 5 ARGSLFHDSSGFYFGH (LCDR1 Ab79) SEQ ID NO: 6SSNIGDNY (LCDR2 Ab79) SEQ ID NO: 7 RDS (LCDR3 Ab79) SEQ ID NO: 8QSYDSSLSGS (Heavy Chain Ab79) SEQ ID NO: 9EVQLLESGGGLVQPGGSLRLSCAASGFTFDDYGMSWVRQAPGKGLEWVSDISWNGGKTHYVDSVKGQFTISRDNSKNTLYLQMNSLRAEDTAVYYCARGSLFHDSSGFYFGHWGQGTLVT VSSASTKGPSVFPLA(Light Chain Ab79) SEQ ID NO: 10QSVLTQPPSASGTPGQRVTISCSGSSSNIGDNYVSWYQQLPGTAPKLLIYRDSQRPSGVPDRFSGSKSGTSASLAISGLRSEDEADYYCQSYDSSLSGSVFGGGTKLTVLGQPKANPTVT LFPPSSEEL (Heavy Chain Ab19)SEQ ID NO: 11 EVQLLESGGGLVQPGGSLRLSCAASGFTFNNYDMTWVRQAPGKGLEWVAVISYDGSDKDYADSVKGRFTISRDNSKNTLYLQMNSLRAEDTAVYYCARVYYYGFSGPSMDVWGQGTLVTV SSASTKGPSVFPLA(Light Chain Ab19) SEQ ID NO: 12QSVLTQPPSASGTPGQRVTISCSGSNSNIGSNTVNWYQQLPGTAPKLLIYSDSNRPSGVPDRFSGSKSGTSASLAISGLRSEDEADYYCQSYDSSLSGSRVFGGGTKLTVLGQPKANPTV TLFPPSSEEL (HCDR1 Ab19)SEQ ID NO: 13 GFTFNNYD (HCDR2 Ab19) SEQ ID NO: 14 ISYDGSDK HCDR3 Ab19)SEQ ID NO: 15 ARVYYYGFSGPSMDV  (LCDR1 Ab19) SEQ ID NO: 16 NSNIGSNT(LCDR2 Ab19) SEQ ID NO: 17 SDS (LCDR3 Ab19) SEQ ID NO: 18 QSYDSSLSGSR(Heavy Chain Ab19) w/constant SEQ ID NO: 19EVQLLESGGGLVQPGGSLRLSCAASGFTFNNYDMTWVRQAPGKGLEWVAVISYDGSDKDYADSVKGRFTISRDNSKNTLYLQMNSLRAEDTAVYYCARVYYYGFSGPSMDVWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKRVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNH YTQKSLSLSPGK(Light Chain Ab19) w/constant SEQ ID NO: 20QSVLTQPPSASGTPGQRVTISCSGSNSNIGSNTVNWYQQLPGTAPKLLIYSDSNRPSGVPDRFSGSKSGTSASLAISGLRSEDEADYYCQSYDSSLSGSRVFGGGTKLTVLGQPKANPTVTLFPPSSEELQANKATLVCLISDFYPGAVTVAWKADGSPVKAGVETTKPSKQSNNKYAASSYLSLTPEQWKSHRSYSCQV THEGSTVEKTVAPTECS(Heavy Chain Ab79) SEQ ID NO: 21EVQLLESGGGLVQPGGSLRLSCAASGFTFDDYGMSWVRQAPGKGLEWVSDISWNGGKTHYVDSVKGQFTISRDNSKNTLYLQMNSLRAEDTAVYYCARGSLFHDSSGFYFGHWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKRVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHN HYTQKSLSLSPGK(Light Chain Ab79) SEQ ID NO: 22QSVLTQPPSASGTPGQRVTISCSGSSSNIGDNYVSWYQQLPGTAPKLLIYRDSQRPSGVPDRFSGSKSGTSASLAISGLRSEDEADYYCQSYDSSLSGSVFGGGTKLTVLGQPKANPTVTLFPPSSEELQANKATLVCLISDFYPGAVTVAWKADGSPVKAGVETTKPSKQSNNKYAASSYLSLTPEQWKSHRSYSCQVT HEGSTVEKTVAPTECS(CD157 Homo sapiens; NP_004325) SEQ ID NO: 23MAAQGCAASRLLQLLLQLLLLLLLLAAGGARARWRGEGTSAHLRDIFLGRCAEYRALLSPEQRNKNCTAIWEAFKVALDKDPCSVLPSDYDLFINLSRHSIPRDKSLFWENSHLLVNSFADNTRRFMPLSDVLYGRVADFLSWCRQKNDSGLDYQSCPTSEDCENNPVDSFWKRASIQYSKDSSGVIHVMLNGSEPTGAYPIKGFFADYEIPNLQKEKITRIEIWVMHEIGGPNVESCGEGSMKVLEKRLKDMGFQYSCINDYRPVKLLQCVDHSTHPDCALKSAAAATQRKAPSLYTEQRAGLIIPLFLVLASRTQL(Benchmark 1; Heavy Chain Variable Region) SEQ ID NO: 24EVQLLESGGGLVQPGGSLRLSCAVSGFTFNSFAMSWVRQAPGKGLEWVSAISGSGGGTYYADSVKGRFTISRDNSKNTLYLQMNSLRAEDTAVYFCAKDKILWFGEPVFDYWGQGTLVTV SS(Benchmark 1; Light Chain Variable Region) SEQ ID NO: 25EIVLTQSPATLSLSPGERATLSCRASQSVSSYLAWYQQKPGQAPRLLIYDASNRATGIPARFSGSGSGTDFTLTISSLEP EDFAVYYCQQRSNWPPTFGQGTKVEIKR(Benchmark 2; Heavy Chain Variable Region) SEQ ID NO: 26QVQLVQSGAEVAKPGTSVKLSCKASGYTFTDYWMQWVKQRPGQGLEWIGTIYPGDGDTGYAQKFQGKATLTADKSSKTVYMHLSSLASEDSAVYYCARGDYYGSNSLDYWGQGTSVTVSS(Benchmark 2; Light Chain Variable Region) SEQ ID NO: 27DIVMTQSHLSMSTSLGDPVSITCKASQDVSTVVAWYQQKPGQSPRRLIYSASYRYIGVPDRFTGSGAGTDFTFTISSVQA EDLAVYYCQQHYSPPYTFGGGTKLEIKR(Heavy Chain Ab43) SEQ ID NO: 28EVQLLESGGGLVQPGGSLRLSCAASGFTFSSYGMHWVRQAPGKGLEWVSRINSDGSSTSYADSMKGQFTISRDNSKNTLYLQMNSLRAEDTAVYYCARGGYYYYAMDVWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKRVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQ KSLSLSPGK (Light Chain Ab43)SEQ ID NO: 29 QSVLTQPPSASGTPGQRVTISCSGGSSNIGYKTVNWYQQLPGTAPKLLIYDNNKRPSGVPDRFSGSKSGTSASLAISGLRSEDEADYYCAAWDDSLNGLVFGGGTKLTVLGQPKANPTVTLFPPSSEELQANKATLVCLISDFYPGAVTVAWKADGSPVKAGVETTKPSKQSNNKYAASSYLSLTPEQWKSHRSYSCQVT HEGSTVEKTVAPTECS(Heavy Chain Ab72) SEQ ID NO: 30EVQLLESGGGLVQPGGSLRLSCAASGFTFSSYGMNWVRQAPGKGLEWVSGISGSGGSTYYADSVKGRFTISRDNSKNTLYLQMNSLRAEDTAVYYCAKDSNYDFWSGYYYGMDVWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKRVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEAL HNHYTQKSLSLSPGK(Light Chain Ab72) SEQ ID NO: 31QSVLTQPPSASGTPGQRVTISCSGSSSNIGSKTVSWYQQLPGTAPKLLIYDNNKRPSGVPDRFSGSKSGTSASLAISGLRSEDEADYYCSSYAARSTNIIFGGGTKLTVLGQPKANPTVTLFPPSSEELQANKATLVCLISDFYPGAVTVAWKADGSPVKAGVETTKPSKQSNNKYAASSYLSLTPEQWKSHRSYSCQVT HEGSTVEKTVAPTECS(Heavy Chain Ab110) SEQ ID NO: 32EVQLLESGGGLVQPGGSLRLSCAASGFTFSSYGMHWVRQAPGKGLEWVSIIYSGGSTYYADSVKGRFTISRDNSKNTLYLQMNSLRAEDTAVYYCARRATWGGATHDYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKRVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQ KSLSLSPGK (Light Chain Ab110)SEQ ID NO: 33 QSVLTQPPSASGTPGQRVTISCSGSSSNIGSNTVNWYQQLPGTAPKLLIYRNNQRPSGVPDRFSGSKSGTSASLAISGLRSEDEADYYCATWDDSLNGVLFGGGTKLTVLGQPKANPTVTLFPPSSEELQANKATLVCLISDFYPGAVTVAWKADGSPVKAGVETTKPSKQSNNKYAASSYLSLTPEQWKSHRSYSCQVT HEGSTVEKTVAPTECS(Heavy Chain Ab19) w/constant SEQ ID NO: 34EVQLLESGGGLVQPGGSLRLSCAASGFTFNNYDMTWVRQAPGKGLEWVAVISYDGSDKDYADSVKGRFTISRDNSKNTLYLQMNSLRAEDTAVYYCARVYYYGFSGPSMDVWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKRVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNH YTQKSLSLSPGK(Light Chain Ab19) w/constant SEQ ID NO: 35QSVLTQPPSASGTPGQRVTISCSGSNSNIGSNTVNWYQQLPGTAPKLLIYSDSNRPSGVPDRFSGSKSGTSASLAISGLRSEDEADYYCQSYDSSLSGSRVFGGGTKLTVLGQPKANPTVTLFPPSSEELQANKATLVCLISDFYPGAVTVAWKADGSPVKAGVETTKPSKQSNNKYAASSYLSLTPEQWKSHRSYSCQV THEGSTVEKTVAPTECS

Having described the invention in detail and by reference to specificembodiments thereof, it will be apparent that modifications andvariations are possible without departing from the scope of theinvention defined in the appended claims. More specifically, althoughsome aspects of the present invention are identified herein asparticularly advantageous, it is contemplated that the present inventionis not necessarily limited to these particular aspects of the invention

1.-30. (canceled)
 31. A method for assaying CD38-expressing cells inwhole blood, the method comprising: a) obtaining a sample of whole bloodfrom a subject with an autoimmune disease, wherein the sample includesred blood cells, white blood cells and an anticoagulant; b) lysing thered blood cells to form a treated sample; c) freezing the treated sampleto form a frozen sample, wherein freezing occurs within about 24 hoursof obtaining the sample of whole blood from the subject; d) measuringthe level of CD38-expressing cells in the sample relative to a controlsubject without the autoimmune disease within about 72 hours ofobtaining the sample, wherein the frozen sample is warmed to roomtemperature before measuring the level of CD38-expressing cells.
 32. Themethod of claim 31, wherein the frozen sample is maintained at atemperature of about −20° C. or less prior to measuring the level ofCD38-expressing cells.
 33. The method of claim 31, wherein theCD38-expressing cells are plasma cells and/or plasmablasts.
 34. Themethod of claim 31, wherein the CD38-expressing cells are plasma cells.35. The method of claim 31, wherein the CD38-expressing blood cells areplasmablasts.
 36. The method of claim 32, wherein the frozen sample ismaintained at a temperature of about −80° C. prior to measuring thelevel of CD38-expressing cells.
 37. The method of claim 31, wherein thelevel of CD38-expressing cells is measured by flow cytometry.
 38. Themethod of claim 37, wherein the CD38-expressing cells are stained withan anti-CD38 antibody conjugated to a fluorochrome.
 39. The method ofclaim 38, wherein the anti-CD38 antibody is an anti-CD38 antibodyconjugated to fluorescein isothionate.
 40. The method of claim 31,wherein the method further comprises measuring the level ofCD38-expressing plasmablasts and plasma cells relative to the controlsubject by assaying for free Ig light chains.
 41. The method of claim31, wherein the method further comprises measuring the expression of abiomarker for an elevated expression level of at least oneCD38-expressing cell-enriched gene relative to the control subject. 42.The method of claim 41, wherein the at least one gene is CD38 or IgJ.43. The method of claim 41, wherein the biomarker comprises mRNA. 44.The method of claim 43, wherein measuring mRNA comprises a PCR method,RNA sequencing, or a microarray chip.
 45. The method of claim 31,wherein the autoimmune disease is selected from the group consisting ofmyasthenia gravis, autoimmune thrombocytopenia, immune mediatedthrombocytopenia, idiopathic thrombocytopenia purpura, thromboticthrombocytopenia purpura, rheumatoid arthritis, systemic lupuserythematosus, inflammatory bowel disease, ulcerative colitis,graft-versus host disease, myasthenia gravis, Sjogren's syndrome,multiple sclerosis, and autoimmune thyroiditis.
 46. The method of claim45, wherein the autoimmune disease is systemic lupus erythematosus. 47.The method of claim 31, wherein the subject has been treated with ananti-CD20 antibody.
 48. The method of claim 31, wherein the subject isunresponsive to CD20 based therapies.
 49. A method of treating a diseasein a patient, the method comprising: a) assaying CD38-expressing cellsin whole blood according to the method of claim 31; and b) administeringa therapeutically effective amount of an anti-CD38 antibody to thepatient, wherein the disease is an autoimmune disease, and the patientwas shown to have, following treatment with an anti-CD20 antibody, anelevated level of CD38-expressing cells relative to the control subject,and wherein the anti-CD38 antibody is an isolated antibody thatspecifically binds human CD38 (SEQ ID NO:1) and comprises: a) a heavychain variable region comprising: i) a first CDR comprising SEQ ID NO:3;ii) a second CDR comprising SEQ ID NO:4; and iii) a third CDR comprisingSEQ ID NO: 5; and b) a light chain variable region comprising: i) afirst CDR comprising SEQ ID NO:6; ii) a second CDR comprising SEQ IDNO:7; and iii) a third CDR comprising SEQ ID NO:
 8. 50. The method ofclaim 49, wherein the heavy chain variable region comprises SEQ ID NO:9and the light chain variable region comprises SEQ ID NO:10.